Combat is cheap drama, and, in my experience, no games deal much or at all with the psychological scars and trauma that real life combat inflicts on its participants. Game combat, therefore, trains people to think in terms of violence as a valid solution to many of life's problems (or most, in the typical game milieu), as free of psychic consequence, and as intrinsically fun.
I think you could make that criticism - if it is a criticism - even more about videogame combat, or film and TV combat. It's pretty well ubiquitous in popular fiction. Except the 'any combat results in PTSD' type fiction, which is no more realistic than 'overnight rest heals all wounds'.
I don't get the impression that fictional & RPG combat trains people to see violence as a solution IRL; I think our brains easily distinguish the two. I do think media can often act as propaganda to dehumanise 'the enemy', which is a different issue.
WoTC went through a phase of "It's Always Demon Cultists" which was a sort of solution to the issue (of Always Chaotic Evil bad guy races existing only to be killed) - the cultists are bad guys, they have clear destructive goals and methods, they don't map clearly onto any IRL group - you can make a link to your preferred IRL Bad Guys, but it's not obvious in the fiction.