I don't think SourceForge is to blame, I think it's FileZilla. SourceForge are only hosting the file that FileZilla have uploaded and are linking to.
FileZilla has it's own site, why would you download elsewhere?
you spend more time unclicking "free offers" than you do installing the damn thing.
WARNING
Unclicking doesn't always work.
I came badly unstuck a month or two ago under circumstances similar to OP.
I carefully read the various install pages and unpicked all the "Free offers" and they just went ahead and installed anyway!
Got it sorted enventually but it was a right PITA!
FireFTP > FileZilla.
No crapware either
But if you don't use Firefox then yeah, .zip version instead of FileZilla.