Changing CentOS in mid-stream

Oh, yes it does; if I make use of or incorporate certain software in my last two jobs, I can be terminated on the spot.

> The copyright holder can't stop others exercising their freedom of association either.

Their attempts to create "ethical licenses" certainly do; under "field of use restrictions"

> The copyright holder can however require that the obligation to distribute modifications to the source be broader, such that others can not wield freedom of association as a weapon to restrict copyleft rights.

The actual "software" has no rights or permissions -- only "persons" do. I (or my employer), as a "person", have the permission granted by the software's author (ie the license) to redistribute that copyleft software. I can chose not to do so for any reason -- Because I don't like you. Because it's Tuesday. Because I promised my mother that I wouldn't. Because I signed a contract with my employer/supplier/whatever to not do so. And so forth.

What you are asking is for the license to unconditionally force/compel folks to redistribute the software to unrelated third parties. There are significant practical and legal problems with that. I'm not saying it's impossible, just that it's going to take a lot of care to draft, and the resulting license will probably see even less use than the AGPL -- Which is already considered so toxic that it's only significant use is as a deliberate poison pill.