You do have to get an invite, seed, and maybe toss them a small crypto donation occasionally. The ratio thing depends on the tracker but usually it's just a requirement to seed back anything for at least a week. Popular torrents become FreeLeech and they don't count against your ratio.
Because the participants are all vetted, you don't get RIAA and MPAA shills in swarm trying to vacuum up IPs to start sending nasty legal letters out.
A decade ago when I used public torrents I remember getting those stupid ISP strikes. I know shit-tier regional ISPs would even try to embarrass you with the content you pirated. They'd send you a letter like "the Copyright holder for 'Anal Hookers of Beijing' told us they're big mad at you, and if you do it again you'll get your service revoked". Some of these ISPs were integrated with cable companies so they'd freeze your internet and cable, and display the text of the copyright strike on your fucking TV for your girlfriend or grandma to see.
Fuck that noise.
Since using a private tracker I have never received a single cease and desist or ISP warning letter. Then again, I only use Bit Torrent to download Linux ISOs.
POV you are walking down the street when you clip through the sidewalk and find yourself in the Backrooms.