It's not ok with the toxic community for Microsoft to advertise features of its operating systems (or let them know of so-called 'bloat'). But it is OK for a company to use pop-ups to request money for their communist endeavors.
First, what do you think communist means?
Second, you have the choice and flexibility to turn such messages off.
Third, if you donate to KDE you are supporting an open and free software, if you spend money on Microsoft you're lining the pockets of a large company.