I don't think FOSS protects you from political activism.

Here's what comes up on my (Fedora, obviously) machine when I run VIM with no filename specified:

                  VIM - Vi IMproved                                
                                                                   
                   version 8.2.5052                                
               by Bram Moolenaar et al.                            
          Modified by <bugzilla@redhat.com>                        
     Vim is open source and freely distributable                   
                                                                   
            Help poor children in Uganda!                          
    type  :help iccf<Enter>       for information                  
                                                                   
    type  :q<Enter>               to exit                          
    type  :help<Enter>  or  <F1>  for on-line help                 
    type  :help version8<Enter>   for version info                 

According to their git history, VIM has carried uganda.txt since at least 2004.

No technical measures exist to stop you from removing this call for donations, but it's more work to patch it out then it is to just ignore it. This makes FOSS software a pretty good vehicle for political activism. Not just the fact that organizing a hostile fork to remove a message like this one is too much trouble and makes you look like a jerk, but also because political activism is a good way to motivate people to write and release software for free in the first place, making up for how difficult it is to really monetize FOSS software.