What you are enjoining is tolerance, which is laudable - tolerance is pretty clearly a good thing. But let's be clear; we tolerate what we disapprove of. You can't tolerate what you approve of - that would be nonsensical.
With that in mind, tolerance requires respect for others as reasonable people and an attempt to understand their point of view. Well, I can well understand that particular points in the combat system of a given edition, say, will cause some people to feel distaste. I can perfectly well comprehend (even if I do not share) their disapproval of general features of the rules or systems. But I cannot, with the best will in the world, see the combat system of 4E (for example) as "pretty shoddy" without some further explanation. "Pretty shoddy" is a claim to poor quality against some sort of objective standard; without some sort of supporting evidence it's not a claim I am going to be able to accept.
But no-one has "changed it away" - 3.X is still what it always was, and Pathfinder appears to be pretty similar in most of the ways people who prefer 3.X find important. The business entity that originally made 3.X has simply made a different game, and one which fills a design space previously uncatered for. Now, if you were to argue that their failure to support the previous editions and strident deprecation of those earlier editions was somewhat foolhardy and distasteful, I would agree with you - but I still wouldn't see how 4E had "changed D&D" save by adding to it.
Actually, I don't think there are anywhere near so many games available for those who like the design features of 4E as there are for those who like 3.x/Pathfinder, but that is really a separate question. Certainly, 3.X D&D is not that game, I agree. But WotC didn't change 3.X - they made 4E. 3.X is still there, for those who prefer that sort of thing. Maybe 5E will be more like 3.X or will otherwise exclude or compromise all the elements in 4E I like; if so, so be it - I will still have 4E and will be thankful that someone catered to the need it fulfills.