Just because HTC don't make official software to sync their phones with Macs doesn’t mean HTC phones aren't compatible with Macs. the great thing about Mac developers is that they are passionate about Mac software. They make alternatives that are just as powerful (in some cases more powerful) than anything that can be made by the manufacturer.
Google it and you'll find plenty of Mac software to Sync a HTC phone that has either Android or Windows mobile OS. Not just just Android, Palm OS , Symbian, Blackberry, all have Official syncing software or powerful alternatives. Some cost money, some don't. but they are there and they are compatible.