The Millers completed the double over Lincoln to move nearer mid-table safety courtesy of Micky Cummins' strike 20 minutes into the second half after good work from impressive winger Jamie Clarke.
Robins had no complaints about his side's work ethic but felt the match official had a less impressive performance.
"It was a hard-fought win, we played some good stuff. Maybe we could have gone on and scored more goals," he said.
"The referee tried his best to give them the advantage all afternoon. There was a tackle on Mark Hudson which would have ripped him in two if it had hit him properly.
"There were some ambiguous decisions, you just want some consistency. Talking about the Respect campaign, it was a poor performance from the referee."