Interesting view. What do you believe corporations shouldn't be allowed to say?
To me the main point is that no person was censored here, and free speech is a human right not a corporate one.
But to answer your question, I would support restrictions on political messaging by corporations, as a side point to heavily restricting corporate political donations and lobbying. I might also support laws that penalize corporations for telling clear lies or misleading statements.
Edit: A word.
See my reply to Mattvision.
I'm not in the habit of tearing down stuff, but if something is going to be torn down - better it's corporate property than individual or public property. I couldn't care less if people wish to deface/tear down advertisements of this type.
Edit: By 'type' I mean corporate advertising in bus shelters, not gay stuff.
Specifically regarding free speech:
I support free speech for people, especially 'little' people. Corporations are not people, and free speech for them should not be a thing.