Roos conceded again after just four minutes against Fleetwood, but then responded with a couple of important saves as his side turned the game around.
Clarke said: "I'm delighted for Kelle. No-one likes to see players made scapegoats, but it sells newspapers and attracts TV viewers so we have to accept it.
"It was great to see our fans give Kelle a great reception before tonight's game and I'm sure that helped. He is going to be a top keeper, but he will make mistakes along the way like everyone else.
"I felt we dominated much of the game, as we did against Peterborough, and once we equalised I was confident that, with the crowd behind them, my lads would get the winner.
"We can now go into two cup ties in a very good league position and knowing we are playing well. As always, the players gave everything and our fans were fantastic."
Fleetwood grabbed an early lead when Ashley Hunter took advantage of a slip by Jake Clarke-Salter to advance into the box and send a fierce right-footed drive past Roos from a narrow angle.
Rovers equalised on 61 minutes, Matt Taylor heading his 12th goal of the season, unmarked on the six-yard line from Dan Leadbitter's right-wing cross.
The winner came on 73 minutes when Cristian Montano found time and space inside the box to shoot home from 12 yards, his shot taking a deflection to wrong-foot goalkeeper Chris Neal.
Fleetwood boss Uwe Rosler had no complaints, saying: "My players gave me everything.
"We started and finished the first half really well and there was nothing between the teams after the interval.
"We made two mistakes and didn't create enough in the second half. Playing here you accept that decisions will be influenced by the crowd.
"There is a good atmosphere around the place because Bristol Rovers are a club with momentum and their fans play a part for them, unfortunately for the opposition.
"Our aspirations are not to finish in the top two or top six this season. They are to stay in League One and get as many points as we can.
"We are still in the top 10 so I am not too disappointed."
Rovers goalkeeper Steve Mildenhall, who was on the bench against Peterborough, is expected to be out of action for several months, having been told he requires knee surgery.