https://www.nfl.com/news/eagles-cb-james-bradberry-on-crucial-third-down-penalty-it-was-holding
A few points:
As you can see in the linked article, the Eagles CB called for the penalty actually admits it was indeed holding: "It was a holding. I tugged his jersey. I was hoping they would let it slide." Thus, from a strict legal point of view, the call was correct! Unlike in the case of pass interference, holding calls aren't limited to situations where the pass in question was catchable, but for the holding.
On the other hand, it was indeed true that the receiver probably wasn't going to make the play even in the absence of the holding, and that the penalty didn't pose any risk of injury. In such cases - especially at key moments of big games - referees will often ignore a penalty and "let them play," on the theory that we should not let the outcome of the game be determined by a dinky penalty.
Thus, the real argument critics of the call must make is not that it was "wrong," as such, but that NFL officials should have exercised their discretion to NOT make a call, even though the Eagles player really had committed a penalty. Refs do in fact often exercise discretion in that way. So too do "real world" law enforcement officers (e.g. - cops only ticket a small percentage of the drivers they see speeding, figuring that it's unjust and a waste of time/resources to punish people who are slightly over the speed limit, but not significantly endangering anyone).
The historical incident this most reminds me of is the notorious "too many men on the ice" call against the Boston Bruins in the waning minutes of Game 7 of the 1979 Stanley Cup semifinals. The nefarious Montreal Canadiens (Boston's traditional rivals) tied the game on the ensuing power play and then won in OT. The Bruins really DID have too many men on the ice. But it wasn't a genuine attempt to keep an extra skater on the ice, but rather a situation where one player was slow to get back on the bench during a line change. Bruins fans (myself included) have always condemned this call on the grounds that the referee should have just "let it go," given the fact the penalty had no effect on the course of the game, and given existing norms of NHL officiating.
Since I condemn the "too many men on the ice" call, I have to do the same in this case. In both situations, officials should have exercised discretion and not allow a dinky technical penalty to determine the outcome of a big game. But there are serious counterarguments, such as 1) officials have a duty to fully "enforce the law," regardless of consequences, 2) they can't be trusted to exercise such discretion fairly, and 3) the teams and players consented to be subject to the rules, and thus can't complain about it after the fact.