They do but in general, if you can have 100 big streamers streaming your alpha test as opposed to 100 randoms, you'll give it to big streamers as that will gather more momentum and get some eyes on the game. Streamers definitely got the majority of the invites to the technical alpha but some randoms also did. I don't even believe they have to say it to be fair. It's a legitimate marketing tool, surely that's well known. Especially in the case of this game as any Diablo 2 streamer still playing the game 20 years later will definitely know more and offer more feedback than some random Billy who got a key.