Honestly from a psychological viewpoint you are completely right but because this is yaoi/BL no one will listen to common sense and would rather the romantic spin. It’s clear as day what red needs is unprovoked affection. That’s ultimately what he’s craving. Granted you can fall in love with someone older than you which is of course a reality. However the specific way the author has presented the Uncle and redhead dynamic really does have a more familial air to it than sexual/ romantic. Redhead is just starved for attention so he became an asshole. It’s a cliche but it is what it is. It’s also why I just don’t enjoy this pairing because the way the author has presented it makes redhead some petulant manchild more so than an adult with clear motivations and exceptions for himself and his partners. He’s not even remotely mature enough to date uncle, that’s usually the most important factor to overcome dating a significantly older partner. I’d recommend an alternative plot that actually realistically looks at and shows the maturity of a cross generational relationship and what it entails within the relationship and under the scrutiny of society.
http://www.mangago.zone/read-manga/ji_ye_and_guan_shan/
The maturity issue is a huge point that people don't seem to care about when they write comments at least. I have read age gaps that seem to work but these two really don't have any real chemistry and Qiu is just pictured missing his father and then there is a picture of Pan. And Pan is not interested in Qiu's money so they will not connect over expensive watches or rides in the fancy car that Qiu tries to impressive Pan with.
Redhead is only looking for a Father figure replacement in Uncle Pan. There is no love there. Only attention that a neglected little rich boy desires.