I missed this question earlier, please forgive me! Glad I got in before the thread was locked.

There are not a great many deaf diarists from the 19th century and earlier (or their diaries are not extant), so information on deaf people's private opinions of signed languages is limited. Marie Lenéru was a deafblind French diarist, but did not use sign language primarily; deaf people certainly gathered and used sign language amongst themselves, as we have robust documentation of deaf clubs and events, but there is not a lot out there about how they felt about the language they used.

We start to see more commentary on sign language after the 1880 Milan conference, oddly - this was a watershed event for the deaf community, as hearing administrators of deaf schools decided that sign language was inferior to spoken language. To this day this remains the perception in most countries, and sign language as a modality still struggles for acceptance. Nonetheless, this event brought more attention to sign language generally (there's no such thing as bad press, perhaps?), so there is at least some more documentation after this point.

An important resources here is the American Annals for the Deaf. The issues from 1886-1925 are free at that JSTOR link, and while it does not regularly note whether an author is deaf or hearing, you can read commentary such as James Denison on fingerspelling being taught in all schools. (Denison was the lone deaf attendee at the Milan conference.) The Internet Archive also has a number of early issues of the Annals available; it started in 1847 and is still published today, but most of its writers have always been hearing.

Perhaps the most significant commentary we have on sign language is from the 1913 film Preservation of the Sign Language, which is on the National Film Registry (pdf link). The film, which is now available with English captions although it did not originally have them, shows George Veditz, then president of the National Association of the Deaf, lecturing about why sign language is important and why it must not give way to oralism in the wake of the Milan conference. That this was filmed in ASL, rather than written in English, is even more important - the NAD felt sign language was at risk of fading, and it was important to document it, which speaks to how others at NAD felt at the time, as well.

More recently, when Stokoe, Casterline, and Croneberg began doing research on ASL and determined in 1960 that it was a full-fledged language, they encountered a lot resistance from the lay deaf community, who had internalized the message that sign language was inferior. As Hochegesang and Miller noted in a 50th anniversary edition of Sign Language Studies, "the initial reaction [among deaf people] was silence and skepticism." It took the establishment of the Linguistics Research Lab at Gallaudet to really start finding enough evidence to prove to deaf people that ASL is a full and complete language; the 50th anniversary paper I've linked has interviews with the Deaf and hearing people who worked at the LRL.

Before the turn of the millennium (which is where our 20-year rule forces us to cut off), you see much more pride in sign language, in the US and around the world. Joseph Hill's 2012 book Language Attitudes in the American Deaf Community has some information from pre-2001, and the Sociolinguistics in Deaf Communities series, started in 1989, is another good reference. JSTOR also has the complete archives of Sign Language Studies (not free) for further reading.