It can be really bad for the industry if ARM is both a producer of chips and the gatekeeper within the ARM ecosystem. I don't know if there are laws against this or loopholes through them, but what is going to prevent them from just withholding license or technologies to push competition out?
I think what they meant by that is "is this different wrt antitrust compared to Intel and x86?"
Intel both owns the x86 ISA and designs processors for it, though the situation is more favorable in that AMD owns x86-64 and obviously also designs their own processors.