CST1229 wrote:
gasstationwithoutpumps
programmingwithpurpose
Spongebobrectanglepants

I believe you.

That first one is so old that perhaps it was created before the Scratch website enforced any character limits on account names (similar to why there are a few 2-character accounts). For the other two listed above, I suspect their usernames were changed but the Scratch Team changing the username to their request didn't realize that it had more than 20 characters.