I don't see a problem with people being critical of the game and/or the direction they fear it's heading. I also understand that those playing and enjoying will feel a right to defend, but you have to realise that a lot of these criticisms being directed are valid. Just because you have no problems launching and running the game doesn't mean that those saying 'they are' are lying. It's all over the web, you can read plenty of these examples and Turn 10 have acknowledged that this is happening too and are working on fixing it.
As for the bringing up of content with an aim to only attack the game, that's a bit juvenile and should not be done. Glitches are in every game, some are rarely ever discovered or seen whereas others, like some of the above, should have been spotted and squashed before release. Like @TimBud above says, they can provide some comedy moments too but they need to be more of the non-impacting variety to do that.
At the heart of it all, as long as the game provides a decent racing experience and has enough of that which came before to keep those who enjoy that aspect happy, then the series will always do well. However, it is good to see that players are wising up to the whole thing and not being afraid to voice their discontent at the changes being brought into the series and its issues.
Commenters who haven't even played the game in question and who use only written word and other media to somehow help validate their opinion more so than those who actually do, will be looked upon lesser and rightfully so. In saying that, this doesn't mean that the player themself is completely right either as opinion is after all, subjective. But, find someone with similar interests and a play style like yourself and getting an idea of what awaits can be made clearer.
In the end it comes down to how the game appeals, works, and plays for you. And if all those are good then that's all that matters really. No?