He's professionally trained and has several academic publications, but he's got an axe to grind. On top of the fact that Renegade History is pop-history, his agenda would make me worried.

This does as well: http://www.huffingtonpost.com/thaddeus-russell/fired-teaching-american-history_b_767172.html

Disclaimer: I haven't read his book, but I had heard of him. This behavior doesn't make me think of a trustworthy source, but it could be interesting nonetheless. My thought would be to remember that everything you are reading is intentionally being shown through a heavy lens.

Edit- since apparently some people think that this comment is "inaccurate, superficial, or disruptive", as evidenced by down-votes let me explain in more depth. His response to academic criticism of his ideas is to accuse his dissenters of intellectual dishonesty, pernicious conservatism or lack of imagination. That is A) pretentious and B) the sign that the ideas can't be defended to academic standards. He portrays his failure not as a problem with his ideas but as a failure of his academic peers. That goes against the core ideal of peer review in academia. He couldn't get his ideas published in academic circles, so he published it for pop-consumption. That doesn't inspire confidence in the material.