Dell dropping support for Ubuntu Linux

I keep getting confused and unhelpful statements from Dell support people stating that Dell is no longer supporting the computers they sold with Ubuntu pre-installed. This, of course, is wrong since companies should stand behind products they sell.

But can someone explain exactly what the situation is and why the change? The closest to a coherent explanation I got is that it's just the same as Dell no long supporting Windows 7 because MS does not support Windows 7.

The problem, of course, is that 20.04LTS is supported by Ubuntu until April 2025.

So I'd love a clear and honest explanation about Dell's policy change.