From what you linked, it looks like it was free earlier, and it became $10. "Moreover, the nominal fee would assist DHS in recovering the cost of administering the electronic registration process. "
Parent comment is correct: They are talking about the "filing fee", which had always existed, and should not be confused with the $10 registration fee.
The situation pre-2020 was that it was more difficult to enter the H-1B lottery compared to now, because the employer had to prepare all the paper forms and write checks for at least several hundred dollars. Now, they can enter a trivial amount of information online and pay a trivial fee, and they only have to do the full filing for employees actually selected.
Also, a comment in the DHS final rule pretty much says the same thing as the parent comment:
> One commenter asked how the nominal fee will prevent large outsourcing companies from gaming the H–1B system, when their revenue is in the billions. A professional association stated that the addition of a $10 registration fee will not sufficiently deter speculative and/or fraudulent filings. Another commenter noted that requiring employers to pay a more substantial fee may protect employees from predatory employers and that we should include a provision barring employers from passing the fee on to their employees or garnishing it from their wages.