Why would agents show a FSBO home for free? They're independent contractors on 100% commission, paying for their own health insurance and retirement- why would they work for free? Do you work for your employer for free?
Buyers are free to find & view FSBO homes on their own, they can easily be found on Zillow and any other listing site. MLS even accepts FSBO listings for a flat $300 or so fee, no agent required