If you really don’t want them, add a script like this in Options > Scripting:
But I would strongly advise you to keep at least the
musicbrainz_recordingid tags. Those are used by Picard to remember against which release and recording your files got matched. If you load files with these tags into Picard, Picard will automatically load the corresponding release. That allows you to easily retag your files without doing all the matching and checking again. E.g. you get updated tags or can easily change your naming scheme if you want to re-organize your already tagged music collection.
IMHO the benefit of having these tags set is far bigger then to worry about a few bytes of extra storage.