Why is one who doesn't learn like a golden ring in the nise of a swine? - if he's not learning then he doesn't have the ring! Similarly - in what way is he like a beautiful woman who uses it to stray. What beauty does he have?!
What's the continuity ti the next part if the mishnah - charus & cheirus? And whats the continuity from the last mishnah?
The mishnah is not talking about bitul Torah. Rather it's discussing another concept - eisek haTorah. The person HAS Torah - the golden ring but is not consumed by it! It doesn't INVOLVE him! So he remains a pig - the representative of gashmius - & so invested in lowly pursuits that it forgeta about the torah it has & dives into the mud!
Only haOSEK in Torah which completely involves the person, he is temporarily not megusham but enwrapped in the spirituality of the Torah - then there is no elbon. He is not a pig involved in mud but an ish asher ruach bo.
With this concept the mishnah continues to explain the equation of charus = cheirus. When the physical form of the letter is non existent, so that all that is there is the absence of gashmi in a complete bind to the tzurah with no chomer, there exists complete cheirus from yetzer. Because the person is mis'aleh uplifted. He ia no longer on the battlefield with the yetzer. He can objectively hover above it all.
Our battles are so difficult because we are megusham. Only haOsek baTorah is out of the trenches.
The Klausenberg Rebbeh said fasting from shabbos to shabbos, singeing skin, galus & unwashed clothes for 6 months didn't stop the yetzer. Just a blatt gemara WITH TOSAFOS. - only THAT forces involvement & releases one from the confines of his guf's gashmius.
The gemara has a hava amina that a bal keri may not say sh'mah. Because its a disgrace to the Torah. But the maskana is Torah is fire & is not mekabel Tumah. Perhaps there was no discussion if a bal keri may be OSEK in Torah either bec a kal rosh cannot be osek or because then it is pashut that the involvement in Torah would purify him. But when he is just saying the words of Torah the hava amina was that Torah would be affected by him instead of the reverse.
Now certainly the yetzer will try to attract the hovering spirit to come back down to enjoy the spoils of the battlefield, but its entirely a different fight from above. Just don't be enticed to come down.
This entire mishnah is the continuation of "umigadalto umromamto al kol hamasim".