Bukowski has caused controversy with his actions on the ABC reality show, after allegations that he played Jamie Otis and Blakeley Shea against each other.
In last night's episode, Harrison spent the night with fellow contestant Sarah Newlon and attempted to get Shea voted out, though Otis was eventually the one to leave.
Harrison, who described Otis as "a sweet girl who means well and expects everyone to be nice and honest", has now criticised Bukowski in an interview with TV Guide.
"He was not a nice guy," he said. "He played all the women, used and abused them, and expected them to just deal with it."
Harrison said he was "really proud" to see Otis criticise Bukowski before she left, but described Bukowski's decision to take Newlon on a date as "stupid".
"If you want to sleep with Sarah, that's one thing," he said. "But to be in the middle of a strategic game where alliances and friendships and relationships are everything and you have plowed through the house like a Vegas buffet, the stupidity is astounding."
He added: "Chris and Sarah definitely made their bed and now they'll have to lay in it. They took a chance to be together and there is a huge target on their back. They're the black sheep of the house."
Bachelorette star Emily Maynard recently defended Bukowski - who appeared on her season - by saying that he is "sweet".
Bachelor Pad continues Mondays on ABC.