I do agree about the DH forums. There are a lot of great players here, helping young Nephalem on their journey and discussing creative ways to hunt. Many of them play the game their own way, always trying to find new builds or new variants of existing builds and sharing the results with the community. And all that mostly with the understanding, that there is not “the best way” to play the game, but only a lot of very good ways.
However, I do not agree with the toxic general forums. Yes, it’s true that there are some trolls over there. But there are also a lot of interesting discussions, great postings and a lot of help. I think it’s unfair to all the good posters “over there” to call the forums toxic just because of some *%&%$§ (self censored 
).
Let me say something about the given examples:
In the salvage thread there are are lot of great replies. For example the guy keeping an original Tasker for nostalgia, remembering the origins of this item. Wonderful! Also there is some discussion abot the game mechanincs, and that legacy items are not upgraded when a new patch comes out. Also fine.
And then there is one poster babbling about his big paragon, and that all the players with low paragons are just noobs. Yeah - who cares? Do you want to play with such a guy? No? Well, then just ignore it. If someones takes the game that seriously, let him go. He may have something to compensate by his big paragon. Little … hands or whatever. (Am I getting toxic right now? Probably. 
)
But is the whole thread (or even the whole forum) toxic because of one poster, who takes a totally different approach to the game than “the average player”, who just want to have some fun slaying demons? I would say: No.
Or the other thread in the WD forums: You wrote there, that you main a DH. Well, for us Demon Hunters double-unity is not a big thing, it’s rarely used. Elusive is better, and Elusive and double Unity is almost only used by very young Shadow Hunters. Later (P1000 and above), you usually have enough tougness through dexterity to use Elusive and CoE. With that in mind, the first response could be read as: “Hey, you are new to WDs, and unlike Demon Hunters we use double Unity here more often. Try it, it will help you a lot!”
Whenever you read something “toxic”, try to think, whether this posting could be read in another way. I may be too naive, but the vast majority of people are quite nice most of the time. Even if they appear to be “mean” in the forums, where -idk- 75% of the communication is lost through “only text” without accentuation (is this the correct term?), body language, facial expression and so on … all this non-verbal communication stuff.
The DH forums are great, for sure. But General Forums are not that bad, either. Imho. 
And, btw.: There are some bad postings here as well. I remember a topic from last month regarding re-rolling Yang, where the first two replies were “roll 9 to 12 discipline, its 300% more damage” … luckily DiEoxidE found that topic as well shortly after that. 
That was a patch or three and quite a lot of paragon ago, but the assistance I’ve received her has helped me gain 40+ GR’s with my UE, learn how to run an N6/M4 Hybrid, jump on the leaderboards with my Shadow, and have a lot of fun developing my ZDH.