Twitter is a one off monolith of a style of social media, in the genre of reddit and facebook. Like wal mart to target and other generic shopping centers.

Twitch is not a generic social media site, its a specific style of entertainment. Like football, its creating a specific event style entertainment catering to people looking for a specific thing.

If their only shared point of comparison is that they are big and make lots of money (which is the same thing repeated twice) then there is no real shared point of comparison.

It doesnt make sense to say twitter is driving you away from the concept of social media, in the same way it doesnt make sense to say walmart is driving you away from the concept of buying groceries.