Why do you assume that there was necessarily coordination? In my opinion it's likely everyone who is dropping Parler came to their verdict independently.
It is certainly possible that they all acted independently, but given how many cases of anti-competitive behavior on their part have been documented in the linked report of the Congress - these companies are not completely honest.
Mikhail Gorbachev used to say "Trust, but verify." I would like to see some verification in this case.
Mikhail Gorbachev used to say "Trust, but verify." I would like to see some verification in this case.