Why was Roosevelt’s Workers Bill of Rights too radical and reasonable to oppose? I’ll even go further, what was “so far left”, that it was ever reasonable to oppose it and be a centrist?

to wit: an “economic bill of rights” to guarantee these specific rights:

Employment (right to work[notes 1])
An adequate income for food, shelter, and recreation
Farmers' rights to a fair income
Freedom from unfair competition and monopolies
Decent housing
Adequate medical care
Social security
Education