Manchester United's own foundation, as all pseudo-respectable centuries-old english football club, is built on the crude exploitation of overworked, underpaid factory workers in the late 1800's, early 1900's by the rich. Many players of those clubs were actually dying before their 30s while the owners were lobbying and conspiring to crush all efforts of unionising.
I have no sympathy for Qatar, any slave-ridden conservative regime, or for the record any of their facilitators in western countries (hi Sarkozy). I'd also easily agree that crimes, offenses, human right abuses committed in the present have more cultural significance than events from 150 years ago. However, it would be great if people didn't invent arbitrary moral frontiers to pretend their support of their favorite emanation of oppression is inherently rightful.
That's without even taking into account that the implication of such threads often is a weird classist, meritocratic worldview, where the people and organisations dominating the sport and society somehow deserve to be here, as if they didn't cheat and bully on their way to the top.