With England on 193-5 and chasing a mammoth target of 371, Australian wicketkeeper Alex Carey stumped Stokes' batting partner Jonny Bairstow as he left his crease at the end of an over.
The controversy - and the booing, and later even some abuse in the usually-staid Lord's Long Room - was all around whether the dismissal was firstly legal and secondly within the spirit of the game.
"I thought it was fair. You see Jonny (Bairstow) do it all the time, he did it on day one to David Warner, he did it in 2019 to Steve (Smith)," Cummins told reporters.
"It's a really common thing for keepers to do if they see a batter keep leaving their crease. Cares (Carey), full credit to him, he saw the opportunity, rolled it at the stumps, Jonny left his crease. You leave the rest to the umpires."
"It was all one motion, there was no pause or sneakiness about it. It was 'catch, throw' straight away," he said.
Stokes was similarly unimpressed by the fuss over the incident, although he added that he wouldn't want to win in such a fashion at the end of an over, which is routinely called by the umpires.
"The first thing that needs to be said is, it is out," Stokes said.
"If I was the fielding captain I would have put a lot more pressure on the umpires to ask them what their decision was around the over and around the spirit of the game and would I want to potentially win a game with something like that happening - and it would be no."
But he said that overall he felt the game, which Australia eventually won by 43 runs to take a 2-0 lead in the five-test series, had been tight and exciting and should not be reduced to one moment of controversy.
"It was an unfortunate situation, but it was an incredible game and I don't think we should be talking too much about something like that," he said.
Asked by one reporter whether there was now any risk of his men resorting to such unsportsmanlike tactics as underarm bowling, Australia's Cummins responded wryly: "Depends how flat the wickets get - might be an option we turn to!"
Check out the full scorecard from the second test with Flashscore.
