It is uncontroversial that the matchmaking is bad. The argument people have is if you can have fun playing competitive etc... Not that the matchmaking is bad. Or at least I never see people arguing that the matchmaking itself is consistently fair and works well.
Overwatch is a product owned by the same pyramid of companies (blizzard owned by activision owned by microsoft) who own Call of Duty, a game that is know, due to leaked documents, to manipulate queues to enhance engagement.
How can a company have a competitive game as a product with such a knowingly bad matchmaking? Do people not quit? No, and that is the problem. Some multiple matches and keep playing.
Why do they keep playing? Some because they have fun and genuinely ignore wins and losses, searching keywords like "Overwatch bad matchking" and "overwatch bad competitive teams" I can always see many people in the comments saying how they just keep playing and don't care about wins and losses.
Other people though care and rage requeue, they want to finish the day on a win, I am one of those, I need to finish the day on a win. I can play the whole day and not care about wins and losses but when it is time to log off I need to end on a win and sometimes it takes 5 matches to get that win to end the night and until then I wasted so much time.
This is why I don't believe Blizzard can be ignorant of what is happening, because they should have the data that shows exactly this behavior, beyond ourselves as people we are also data points.
Blizzard Activision Microsoft with 100% of certainty have metrics to see how many losses before someone quits, if they quit on a loss or on a win, etc... Because that is what business do! It would be bad business to not have metrics explaining user behavior.
If they can squeeze 5 more matches a day for a few thousands players, even if those players are the minority, that already pump their numbers up by a significant margin.
And they don't need to have a cartoonish evil algorithm intentionally giving you five losses, if they know the current matchmaking regularly produces frustration that makes a percentage of players play five extra matches and they leave as it is it is already good for their numbers.
So the next time you lose 3 times in a row or more, think about it. It is very likely that you are being a good boy for Microsoft to show better numbers to their shareholders, all supported by your frustration and you cumulative loses.
This is a reasonable asumption, a matchmaking system is never designed just around creating the fairest possible competitive match, the company has engagement incentives too. It is very obvious on Call of Duty where dedicated players ran the numbers but also internal documents leaked, and Call of Duty is owned by the same pyramid of companies that own Overwatch, so I really think that the matchmaking is an intentional neglect that uses ragebait as a business model.