This is a good question, one that many historians have tried to answer. But, as you can imagine, it's difficult to answer a question that deals with the personal religious choices of millions of people. There will always be more that could be said, but I will focus on one case study to give you an idea of the kind of decision making process people might make.

First of all though, it must be pointed out that Calvinism was usually a minority faith. Your average French peasant remained Catholic. Even in countries where the Reformed Church was the state-sanctioned church, like the Dutch Republic, the Reformed Church did not make up the majority of the population. The strict discipline that was required in Reformed or Calvinist churches was a deterrent for many. As a result, when Calvinism became a state religion, the government was often forced to offer some degree of religious toleration to other sects. Thus, some of the points you mentioned definitely turned a lot of people off.

So why would someone become a Calvinist? Let's take a look at the Dutch lawyer Arnoldus Buchelius (1565-1641), who during the later half of the sixteenth century abandoned Catholicism for Calvinism. I’ll base my answer partially off the book Religious Choice in the Dutch Republic: The Reformation of Arnoldus Buchelius by Judith Pollman. If you want a more detailed look at the appeal of Calvinism, I highly recommend it. Buchelius is such a useful case study because so many of his personal writings (diaries, correspondence, autobiography) survive.

Buchelius was privileged enough to receive an education and was therefore exposed to Christian humanism in his hometown of Utrecht and on his travels in France. During the 1570s and 80s, Buchelius remained committed to Catholicism, but criticised what he saw as a misguided focus on outwards expressions of piety, such as doing penance and taking part in religious processions. Erasmus made similar criticisms half a century earlier and it can be argued that the Lutheran reformation also gained a lot of traction for its famed criticism of the sale of indulgences. Calvinists were definitely able to tap into this discontent to gain adherents.

While Buchelius was exceptional in his level of education, his views reflect a wider religious reality at the time: people’s religious views did not necessarily fit into clear-cut religious divisions. The French historian Thierry Wanegffelen noted that many people’s religious allegiance fell “between the two pulpits” of Rome and Geneva. While many were critical of the perceived corruption in the Catholic Church and disagreed with some of its doctrines, that was not necessarily enough for them to leave the church altogether. Others bought into the Calvinist claim that they were preaching the true Christianity of the scriptures, a point driven home by the focus on preaching in their religious services, as opposed to the Eucharist-focused worship of Catholicism. Even so, those initially attracted to Calvinism did not necessarily agree with all of its doctrines, but generally preferred a form of piety focused more on preaching and Bible reading. Viewing religious allegiance this way helps explain how religious reform movements could swell up for a period of time, before settling down into a more permanent religious configuration, whether that be a return to Catholicism or an entrenchment of a new religious identity.

The conversion of Buchelius to Calvinism fits into the model I just described. He appears to have been basically religiously uncommitted until he joined the Reformed Church in the 1590s. Around that time he began regularly taking notes on sermons preached in Utrecht’s Reformed church but he does not appear to have suddenly become a hardcore Calvinist. His library remained dominated by humanist rather than Reformed works and he didn’t really write about Calvinist theology. Instead, he seems to have been attracted to the Reformed church as an institution to bring about religious unity. He saw Catholicism as idolatrous and feared that religious division would lead to scepticism and chaos. He wrote that he believed the Republic’s tolerance of Catholicism would “aggravate the wrath of God towards our lands.” He aligned himself with the Reformed church because of a basic sense that they were preaching religious truth and that they could bring about religious unity. It was only over time that he appears to have become a truly committed Calvinist. By 1620 he had even become an elder in the church. He wrote increasingly negatively of other sects (despite maintaining close friendships with religious dissenters) and demonstrates a greater understanding of Calvinist doctrines. Predestination actually seems to have given Buchelius comfort. Indeed, at a time when natural disasters and military defeats were often attributed to God’s wrath, believing that you are one his chosen people could quite understandably bring some comfort.

Buchelius is just one person of course and his experience was unique in many ways, but his religious journey fits a pattern that was common in the late sixteenth and early seventeenth century. In the mid to late sixteenth century the religious battlelines had not been fully drawn and many people’s religious identity fit somewhere in the middle of the religious divide. Over time, as religious boundaries hardened, people were in one way or another forced to pick a side. Often their choice was not a wholesale acceptance of one religion or another. It was only over time that people more fully adopted the doctrinal positions of their chosen religion. This was part of a concerted effort on the part of both Protestant and Catholic clergy to educate their adherents in correct doctrine and to vilify those on the other side of the religious divide.

I hope that at least partially answers your question. I might be able to provide some further clarification if you'd like.