I agree the guy has pretty weak communication skills and it's no great leap to think a codexer might be out for lolz, but it might just be someone who played a shitty game and then looked for somewhere to vent. I've done that in the past with games, as in played something, been disgusted by something, searched google for a related forum about it, reeled off a stack of hatred. These things happen.
With this site there does seem to be a very predictable contingent who respond to these kind of posts in a sort of unified and predictable way, as if certain forms of posts are like respawning monsters in a Wizardry game that need to be killed by a turn-based blob of the 4-6 predictable poster team.
Dragon Age 3 is not a game which inspires polite conversation. Its not a game which inspires very much gameplay conversation. Like Dragon Age 2 before it its a game which inspires vitriol and mockery because its asking for it, one because it was shoddily made and the other because it was such a departure from series expectations and that those departures were themselves laughable silly.
Of course personal taste is going to effect someone's appreciation of a game. Of course there will be elements of the game that will be ok. Of course there will exist someone on this earth who thinks its their favourite game. But this is a site which is supposed to attract RPG specialist fans. People who, when offered a group of games to play, will first take interest in the RPG that is on offer out of the bunch. And I dunno about you but you would have thought that Dragon Age 3 would be exactly the kind of game that would likely get more stick on an RPG forum than a general gaming forum. Especially a gaming forum which is dedicated to PC RPGs more than console RPGs.
I really don't think it would have mattered how politely or well spoken the guy was, I think the same team blob would have been out in force no matter how the guy vented.