Impeachment proceedings are not judicial proceedings; they’re political ones. Both processes use similar language because the process is similar, but they are not connected. Commission of a crime is not required for impeachment proceedings and being impeached by the House and convicted by the Senate conveys no criminal punishment.
This is, effectively, how oral flee/tick medications work in animals. It basically turns the animal’s blood into a mild poison. The poison is mild enough that it doesn’t affect the animal but it’s enough to kill small insects like flees, ticks, or mosquitoes.