Robinhood GME halt: please explain

Ok, I tagged on RH as much as any of you but been reading a lot about trade settlement requirement on brokers and am willing the re-examine my ire, but:

1. RH has a relationship with citadel, which is somewhat incriminating since they are loaning money to Melvin
2. Doesn’t RH have their own clearing house? Seems like they should have seen this coming, no?
3. While “it was impossible for brokers to execute those trades”, fidelity and Schwann managed just fine
4. The volume is about 50 mil shares. That’s high, about 2x “normal volume” (though normal has obviously been growing in the last month) but it is about the average volume of Tesla. RH handles a lot of various securities and while most of us are dumping money in GME we are not dumping money into TSLA or anything else. I get the requirements are higher but are they really that fragile? My real-time prod services will not blink at 5x the average daily volume (100x I’ll probably get paged). I get that this is a huge move for GME but minuscule for the market.
5. There was no communication, no warning... thank for the explanation 24 hours later but have any of you ever done something bad and then had time to think about it, talk to lawyers, see what others have done and some time later come up with a perfectly reasonable explanation? In conjunction with 1 this is peculiar, no?