That's a common practice, goes back decades. Bush did too. I looked it up.
Still doesn’t matter. Bush was right to get rid of those who would not prosecute Clinton for his illegal activities. Bush did it to remove the filth.
I had heard that the tradition was to replace them but not remove the current US attorney until the new one was selected and ready to take the seat which might take months for some at the bottom of the list. Clinton broke that by firing the old ones long before he had replacements.
Would you share your source? I recall that when Clinton fired all 93 US attorneys, it was a first, and a pre-emptive step because he was bringing a new level of corruption to the White House and already had some then-current budding issues already being looked at by existing DOJ lawyers.
Not saying I'm right, but I'd be interested in your sources.