Today was admittedly very difficult. The Chofetz Chaim in footnote 17 was trying just to be honest and not make people think that we have to go to the extreme and say something is forbidden on a Torah level when it really isn’t. The case we are dealing with is when one is too lazy to get up and leave, granted he is disgusted with the lashon hara he hears and has no intent to accept it as truth so he does not transgress the Torah prohibition of accepting lashon hara but he was just too lazy to get up and leave though he had a chance so he gets a rabbinic prohibition of not actively staying far away from lashon hara. The Chofetz Chaim asks why he doesn’t get a Torah prohibition just like a married woman who was kidnapped and was given the chance to leave but doesn’t so if her capturers have relations with her she is now forbidden to her husband because she showed willingness by not leaving when she had a chance whereas beforehand when she would have been permitted to her husband because anything the captors would have done would assumed. To have. even forced against her will. Furthermore we see by Esther in the Purim story that she only became forbidden to her husband, Mordechai, only after she invited Achashverosh to her party and he had relations with her that night, for until then she was just completely passive letting Achashveirosh do whatever he wanted and not having any delight in what he did, but when she invited him to the party, even though her intent was only to save the Jewish people but she now showed willingness to be with him. Why is the person who could have gotten up but didn’t only out of laziness and therefore privy to lashon hara any different then these women and the red fore also get a Torah prohibition for not leaving? The answer is that he is still different because we know his intent is not to have any benefit from the lashon hara and no rebuke could have stopped them from speaking the lashon hara and on the contrary he was disgusted at what he heard, so on a Torah level he did nothing wrong it is just that the Rabbis said you should put your finger in your ears or walk away and he was to embarrassed and lazy to do that so he only has a rabbinic prohibition. But these women must acquiesce at some degree to being to their kidnappers because why else would they be forbidden to their husbands just because they were too easy to go home? And with Esther, though she was just doing it to save the Jews but because she initiated the party know what would happen that night it shows some level of willingness which forbade her to Mordechai. Whereas the one who sat down to eat did not realize any lashon hara would be spoken so he isn’t as bad though he still should have gotten up when he had the chance.
Note 18 said that though the gemara in Kesubos says you should put your fingers in your ear which will make it hard to hear and might stop them from speaking because they see you do something abnormal which will tip them off to stop but nowadays people think you look like. A fool and ridiculously funny and will just make fun if you so it is better to just walk away.