After the US established its Space Command the need to find or invent any trace of hostile activity in space grew accordingly.
Looks like the current US administration is planning to deploy weapons in space and need to break one more treaty, as they did several times already (started with ABTM in 2002). And accusing the other side seems to be the only way for them. Boring old stuff...
Accusing Russia that "a space object of unknown purpose separated from a satellite" is laughable. Even if (just an assumption) it is an inspector-type satellite, they appeared in 70's on both sides, nothing new.