I don't want to go out of my way to defend the tone on this site. I think we're generally doing an adequate job of maintaining a respectable atmosphere here, but people have made and always will make mistakes. There is always room for improvement and I respect your decision to bring that up.
However, the examples you bring are poor at demonstrating a continuing tone problem. For starters, they are all Meta posts (posts about the site itself, rather than questions and answers about RPGs). Even in Meta we do require courtesy and politeness towards other people, including those who are not immediate parties in the discussion at hand; however, we have to accept a degree of critique towards other peoples' posts in order to discuss potentially deleterious trends. (Notice that all of you examples concern trends, not individual questions, and each but the first one have more than one example provided)
That is not to say all critique is acceptable, and this is where I think you do have some point. I would certainly not be cool with making a list of "terrible" questions, though I must say I see where the author of said post was coming from. The post was authored in a time when the site was practically flooded with questions about the yet-unreleased DnD 5e, and the concern that it was more about people spinning over-excitedly in hype for the game rather than genuinely try to solve problems was an understandable one. That was a different time, of course, which brings us to the next point...
...all of these posts are old. Two from 2014, one from 2010. That's... ancient history, as far as this site is concerned. I won't hesitate to say that the community had a harsher tone back in those days, nor am I hesitant to say I'm glad it's changed. Several active site users, including moderators, were a fair bit more brusque in their communications than I would like. Nowadays, my feeling is the community as whole as well as the moderation staff holds themselves and each other to a much higher standard of courtesy.
Nevertheless, incidents happen and will continue to happen, and that's where you (points at the camera) can help! Flag posts and comments that are rude, use the "needs moderator attention" reason and a custom message if you notice a pattern that might not be evident from a single message. Remember that posts do not have to be explicitly offensive to be flaggable: in addition to "plain" name calling, low-key things like egregious condescending tone or snarking can be flagged. Contact the moderators for a 1-on-1 discussion in chat if you need to discuss something that cannot be covered by flagging.