Looks like you're right, this is breaking their TOS:
>4) Since there are only limited numbers of connections available for streams, and because the site is funded through advertising and donations, you agree to consult LiveATC.net prior to linking directly to any of the audio streams. When you do link you agree to give credit to LiveATC.net with a prominent link to www.liveatc.net.
There is a link to LiveATC. It isn't clearly labeled, but that isn't required in the TOS and since this site has been up since at least November of 2021, I expect they're fine with it.
>4) Since there are only limited numbers of connections available for streams, and because the site is funded through advertising and donations, you agree to consult LiveATC.net prior to linking directly to any of the audio streams. When you do link you agree to give credit to LiveATC.net with a prominent link to www.liveatc.net.
Not nice.