The deceptive aspect is the stronger part of the objection. Banning any and all political messages in Debian packages would go too far and I doubt the community would support it. People and in extension developers, can be quite political active and will put some of that into their works. I am sure (as in I don't need to verify) that the pride flag is somewhere in Debian right now, in some package, and banning it would cause much more conflict than allowing it to remain where it is. The problem really only exist if people would have it shoved into their faces through deception.

An other example of political message is when projects redirect donations to a cause. Should projects be banned from having a "donate to Ukraine" somewhere in a program, maybe with a Ukraine flag next to it?