I have the same problem as you. Sorry Yekke, edited a bit-29The variety of reading material for a Jewish teen/adult is sorely lacking.
Although my parents were very careful to censor what I read, I did end up reading things that I regret reading. I don’t read secular books any more, and I can’t remember the last time I read a Jewish novel. My reading is limited to articles in Jewish Magazines [Mishpacha, Binah, Ami, etc.] (- some of which have surprising amounts of toichen!).
As a Yeshiva Bochur it is less of a problem than a school-aged teenager or a girl – during zman, someone who is correctly motivated doesn’t have time to read anything [obviously this doesn’t apply to everyone], and even bein hazmanim there is a lot more interest in a broader range of Torah subjects; dozens of fascinating seforim which we can learn even during time set aside to relax.
However, ‘lack of options’ isn’t a reason to be mattir something which is wrong. If there is something wrong with the book, the lack of kosher alternatives isn’t a hetter.