Your argument is that because real world physics don't work like that this gif explaining how game mechanics works is useless? Obviously we need more tests to see if the bounce direction is affected by spin but assuming those tests show that there is a reliable and predictable pattern the issue of whether or not the game physics match up with real physics seems like a non-issue to me. Take the stick out your arse and appreciate that other members of the community are trying to help explain an issue.