"Yeah ... as someone who reads 150-200 novels / year". Yeah I very much doubt that, very condescending of you to feel as though reading that much novels give you better narrative and storytelling skills. I'm curious on how the protagonist would enforce an "underground railroad" system if implemented, the lack of resources is one factor. Also where would the enslaved elves run to? Pretty sure the entirety of Syl'anar is dominated by pro-slave humans. I very much doubt Syl'iath (who don't want to risk revealing themselves) nor the Resistance (who are already small currently) can manage enforcing a "underground railroad".
(SPOILER WARNING)
Alright to refute some things off on what you stated.
- Why would they be arrested nor shot by the government? From what I understand, the government have no evidence of any illegal business the protagonist has been secretly doing so far. The protagonist is seen in a positive light by Cornwall (so far) who is the Minister for the Elves. Also adding to the fact that the protagonist have girls (Kali, Felicity, and Emma) who's father are in high position which deflect any suspicion.
- Also, no defense? Android with an semi automatic rifle, Nia who knows how to fight, and invisible fairies that know lethal spells. But no defenses, right?
- Autumn is very much involved and informative on the religious organization and Kali has some semblance of political understanding, the protagonist gets information on these topics from various characters so I don't understand how you can interpret that the protagonist lack any critical information.
- The Resistance and the wild elven tribes are currently allies (thanks to Lin and Nia) albeit rocky at best so it not like the protagonist lack any sort of military power. There is also the possibly Syl'iath in the future can be convinced to take side with the protagonist.
- Runey is absolutely right, what would the protagonist have done by running out to assist Lin in the protest? Endangering the other girls and the hotel? Even if the outcome is Lin becoming a criminal at least she made an huge impact.
I'm curious, did you even pay attention to what was happening in the story? Like the issues you stated were already addressed or could be pieced together.