Ok, there is a logical trail here to find. Here is a question and a response from yesterdays AMA:
As you notice, in the question its stated “no LFG in Wrath”.
In the answer part it states: “The guiding principle for WoW Classic was staying faithful to the original game.”
It also states this: " it is likely that some features of these expansions will not be universally embraced by the Classic community."
Now I understand he is talking about the expansions. But when you tie the logic to what he describes you can get a conclusion.
Classic community is against LFG in Wrath. You could surmise that the classic community would be against it in TBC as well. Why do you think they are against these in future expansions? Because they are against them now.