This isn't even my tangent, so asking me what my angle is makes no sense.
1) I said Democratic and AOC's policies are mainstream because most people support them.
2) Someone said as a counterpoint that the Democrats lost the last presidential election, implying that meant their policies aren't mainstream.
3) As evidence that they were mainstream I noted that in that election Democratic policies got millions more votes than the alternative. ie: most people supported them.
4) Now you're saying 'why does that matter, they lost the election'. The election never mattered to begin with, that was your guys' point!
My point is very simple - mainstream policies are most easily defined as policies that the most people support. The evidence is that most people support the Democrats' policies. If other people want to argue that conservatives get to win elections anyway because of institutional bias in their favor have at it. It doesn't change what most Americans want.