The Blades were on top for long periods in the match despite the final score, and Speed was aggrieved after Chris Dagnall appeared to handle the ball for the Iron's opener.
Additionally, referee Neil Swarbrick ruled out a Johnny Ertl effort from the home side, before waving away Richard Cresswell's penalty claims.
Speed said: "I've been here for two-and-a-half years now and I've never known a team be given so little on a consistent basis.
"Maybe officials come here with a pre-conceived idea of Sheffield United.
"It cost the previous manager (Kevin Blackwell) his job this year and now it's keeping on. It's getting beyond a joke but I must stress that's not an excuse for the performance."