i assume they are referring to the conglomerate that owns most dating sites

Match Group (wiki link)

I hate this whole social media ban, but this is a self assessment to determine if they are a social media platform which probably won't apply to GitHub. From The Register -

"At first glance, GitHub will not have to deny service to Australians under 16 years of age, because the criteria that require a platform to do so are:

Having the sole, or a significant purpose, of enabling online social interaction between two or more end-users;
Allowing users to link to, or interact with, other end-users;
Allowing users to post material on the service;
Hosting material that is accessible to, or delivered to, end-users in Australia"

And anyway, the ban only applies to logged in accounts, so you can still visit sites without being logged in without restrictions. At least, initially. The whole thing is such a waste of time and money.