That could be true; however, anyone who posted in the D2R forum are not those people. Therefore, D2R forum posters are those who bought it immediately (or with 2 weeks or so) after D2R was announced. Many forum poster have stated that they purchased D2R during the two days of Blizzconline.
Therefore, those expressing their views on the D2R forum are not the ones holding off on buying D2R to make sure it isn’t W3R. Therefore, the sampling bias in the D2R forum is highly skewed.
Also, I will add have you checked the discussion in the D3 general discussion, in particular this thread?
https://us.forums.blizzard.com/en/d3/t/d2r-personal-loot-is-a-must-for-this-game/27592
Now, I know you may discount the opinions of folks on that forum, but there is a 550+ post thread there where people are discussing D2R in detail. In that thread, personal loot/options are more popular than FFF-only. I see alot of people wanting more D2R changes across multiple platforms.
Irrespective of the precise ratio, I think that is fair to say that there are a significant fraction who want FFA and those who want a different loot system or at least an option.
If you are right that FFA>>> other loot options, you have nothing to fear in allowing choice. In this scenario, most players if provided a choice will pick FFA and the non-FFA will be a ghost town. If D2 purists are the majority, there will be nothing (or very little) left for the designers since the playerbase will block all additional changes.
If you are wrong about FFA>>>loot options, then you may see why giving a choice was good for the playerbase more broadly.
In terms of using “likes” to judge popularity, the “top” thread in the D2R forum by a huge margin is this:
Why is the amazon so ungodly ugly? - Diablo II: Resurrected / General Discussion - Diablo 3 Forums (blizzard.com)
The OP has 283 likes that dwarfs any pro FFA-only thread by a huge margin. I would be careful about using forum likes.