I've kind of taken the way the Lizardfolk and the Kobolds in OOTS are treated as running contrary to the Dark One's story and therefore reason to suspect the Dark One's claims.

That or he tries to cultivate a victim complex while the Lizardfolk and Kobolds of the Western Continent said "screw that" and actually tried to make things better for themselves without resorting to potential omnicide.
Actually, I think it's quite consistent with RC's backstory. The Western Continent appears to be a largely inhospitable desert - one of those second-rate environments with which the Gods stuck the monster races.

The Western government run mostly by humans, with only a token representation by the reptilian minority groups among the upper echelon - there's Malack, that one lizard with the monocle, and Kilkil, who's just a minor functionary anyway. To me, this looks a lot like the humans came in and displaced the lizardfolk living there, and assimilated them into the human, Western God-worshiping culture.

While I don't necessarily approve of RC's methods, his people seem to have their own religion, their own culture, and their own identity. Should they just give all that up, start going to Thor and 12-Gods temples, and assimilate the best they can into a society that isn't inclined to give them a fair shake?

I mean, we've seen Redcloak's village get wiped out - including younglings - by Azure City Zealots, without any indication being given that these particular goblins had harmed a single human. In fact, unless I recall incorrectly, none of the pallytards even accused them of having done evil - only that the 12 Gods had judged them evil. Clearly, there are differences between how the reptilians on the Western Continent and goblins and orcs on the Eastern Continent are treated.