Stack overflow and GitHub both allow you to make public posts and interact with others. The text targets public user posts and interactions between users explicitly.

Whether the consequences are intentional or not is still to be determined.

but are they made available by a "social media company"? and should that be relevant?

Well, here’s their definition of such a company (from the same link):

155 (9) "Social media company" means a person or entity that: 156 (a) provides a social media platform that has at least 5,000,000 account holders 157 worldwide; and 158 (b) is an interactive computer service.

So, size is really the only relevant discriminator.

> So, size is really the only relevant discriminator.

No, its not, see the vast horde of use/function based exclusions starting at line 165 comprising code section 13-63-101(10)(b).

None of which clearly protect GH or SO, the subjects of this thread branch.

> None of which clearly protect GH or SO, the subjects of this thread branch.

I disagree, see https://news.ycombinator.com/item?id=35310413 (especially considering that because this law creates a penalty, and because it restricts speech, its definitions of the covered parties and conduct must be read narrowly – and its exceptions read broadly [0] – per the rule of lenity in statutory construction.)

[0] if, in the first instance, it is Constitutional at all.