This refers to physical impediments. Spreading legal information is not an impediment, it is free speech. If all info could be interpreted as impediments to federal officers then phones, the internet, the human voice, etc would be illegal
We already know that "doxxing" on its own is not a crime, and moreover that [non-undercover] federal agents are not entitled to keep their identities secret.
We also know that legal observation and making noise does not constitute interference.
So those may be their stated reasons, but they will not hold up in court.