You can look at it how you choose but it's no coincidence that the amount of passengers denied boarding for "irregularities" has increased dramatically in line with the increased amounts of compensation airlines have to pay passengers for not allowing boarding. Overbook a long haul flight by 10 seats, not uncommon, and that's 6000 Euros owed in compensation and there are an ever increasing load of claims companies out there happy to take on your case. Hence airlines increasingly looking for ways to avoid paying out on overbooked flights. Point is that a less than 100% correct ticket/passport/visa is far more readily pounced upon when a flight is overbooked than when it isn't.
Also the "photo" was not the issue here, it's not even a photo, on this issue of passport it's printed onto the page beneath the laminate, can't be substituted and also printed on the facing page as in the image below from https://www.gov.uk/government/publications/basic-passport-checks/basic-passport-checks-accessible
Qatar were just trying to avoid paying out for overbooked flights, end of.