Musk also claimed that they would land on Mars in 2022 lol

Also, just because a rocket is capable of landing on Mars doesn't mean you'll send humans on it. You would first need to verify that it can get there, land AND take off again and return. That will require several trips to Mars to verify and that's assuming everything goes according to plan and there's no setbacks.

Plus, he's basing his estimation on the aspirational performance of a rocket that doesn't exist yet. They've changed their design quite a bit already, which further invalidates his estimates.