I'm assuming that you don't know a whole lot about Traditional Doom Metal in general if Pentagram is the band you're pinning the Sabbath copycat tag on. Pentagram was damn near a contemporary of Sabbath, having formed in 1972 I believe, releasing several demos and singles throughout the 70s and early 80s, until they finally landed a record deal and released two albums in the mid to late 80s. The took much more influence from bands like Blue Cheer and Sir Lord Baltimore than Black Sabbath, though the obvious monolith of Sabbath of course looms large over all Doom Metal that followed in their wake, even to this day. Liebling most likely borrowed the "ooh yeah"s more from the Rolling Stones (whom they've actually covered) than Black Sabbath, actually. They had a much more rock oriented approach than Sabbath in many ways. With all that said, I suggest you check out their early works, and I would also say that you don't know what you're talking about if you think that
Be Forwarned of all of their albums is a Sabbath ripoff.