Komplex, it sounds like you know a little bit about sampling legality and near to nothing about sampling itself. And as regards the foul Pete Rock talk....times were you'd get a smack in your mouth for words like that.
When Pete Rock used an old Jazz drum hit in a beat, he did HEAPS to recontextualize the sound (compression, filtering, EQ'ing, Tuning, Pitching, cutting/scratching etc.) The sound of the drum that you take off of a Pete Rock record isn't just the drum taken from an old record that he originally found, but the drum with all Pete Rock's work put into it.
If you are making Hip Hop beats, you should be putting that work in yourself with your record collection, not just collaging the slamming beats other people have worked hard to produce.
Pete Rock mainly sequenced his drum hits, rather than rely on looping breaks (not that looping breaks is bad).
Incidentally, you can copyright drums the same way you can copyright music written with any other instrument. It's just that it doen't happen much because a lot of sampled people didn't "write" or compose their drums. they just bang away on un-tuned skins. Jazz guys and gentlemen like David Axlerod wrote drums, though.