When the same thing was done in response to the BLM riots, there were howls of outrage, so I'd rethink the idea of cheering when the FBI goes after your enemies but crying "injustice" when it goes after your friends.
I’d like you to consider the problems with giving executive branch (FBI) power to monitor legislative (congressional members) without a warrant.
Our intelligence agencies have vast power now, and have been largely enabled by sympathetic tech companies. I wouldn’t be surprised if we find out the FBI has a record of every SMS conversation that happened at the capitol.