Rovers looked to be on course for a second consecutive home win after Sam Gallagher's stunning 13th minute volley - his sixth goal of the season, but Edwards' second goal of the campaign denied the hosts.
Wolves' goal came just three minutes after a noticeable walk-out by the Blackburn fans in protest of the club's owners, Venky's.
But Coyle said he did not think that made a difference to his side conceding, the key, he said, was a "frustrating" call from the assistant.
"We scored a wonderful goal to get in front and had a couple of opportunities to get that second goal, albeit they still had one or two things themselves," Coyle said.
"The galling thing is their goal is clearly offside. When the shot's been taken, the boy that crosses from the wide area is two yards offside. It's ridiculous. It's two home games it's happened to us now. It happened against Sheffield Wednesday when we scored a perfectly good goal and today the boy is clearly two yards offside.
"It's galling, it's frustrating. If they score a wonderful goal, I'll hold my hand up to it but when things like that are punishing a team that are working ever so hard, then of course it's very frustrating.
"The frustrating thing is that's such a simple decision because you're actually looking right along the line. That's not a centre back trying to step up or a striker running in. That assistant's looking right along the line. The first person he can see is the ball that's offside so I don't know how he could possibly get that wrong."
In the week that Wolves parted company with Walta Zenga, they put in a spirited performance to claw their way back into the game.
Despite the result stretching their winless run to six games, the point stopped the rot of two defeats before this.
And interim manager Rob Edwards was understandably proud of the way the players performed.
"I felt we deserved a point, we were good value for it. I think 16 shots away from home, you deserve a point," he said.
"We had some good play, we were a little bit loose without the ball, a little bit open. That's something we spoke to the players about but in terms of work rate, commitment, spirit, the players were fantastic and they gave us everything," he said.
"I thought, with the ball, I was really pleased with a number of players. It would be unfair for me to single anybody out because I could pick out something great from every single player but in possession.
"I thought the amount of shots and chances we created was really pleasing because there were elements of things we had worked on. We got a lot of crosses in the box and had shots in good areas. That was a really pleasing thing."
Edwards is not entering into the merits of taking the job full-time at the moment, though.
"We'll just carry on until we're told otherwise. Our focus goes on to Derby," he said.
"It was an incredible experience. To be doing it out on the touchline, leading Wolverhampton Wanderers out, was a really proud moment."