Because Lezhin knows yaoi is more profitable. I know most readers likes to put Lezhin on pedastal but unlike other Korean webtoon sites, Lezhin always been profit orieted tbh.
Shoujo ai and Yuri are scarced. Unlike BL, you can see almost every an hour an update.
If you look at the Korean version of Lezhin, you can see that the webtoons that are not for mature audience even unlock free episode every week, so basically if you're willing to stay a bit behind you can read all episodes for free. The mature webtoons, however, stay unlocked forever :(
This is because Lezhin knows that people are willing to pay more for mature content. Price discrimination is at work here, sad but every for- benefit company would do the same.
shoujo and shounen are the most profitable ones and are aimed at younger audience. it has a lot of readers (that mostly need money from their parents) so it's the best to be cheaper and to have more free content.
a lot of bl comics are mature and most of these sites always make you pay for mature content. not because they are sure you will pay but because it's way more easier to control who reads it, since it's forbidden for people below 19. it's better for us to have to pay for them than to be like on foxtoon where you needed to confirm that you are 19+ trough your number and you needed korean number, so even if you wanted to pay for it, you couldn't since you aren't from korea.
aand my guess is that they think foreigners are more rich than koreans, that's why some webtoons are more expensive on english site than on korean xD
On ethical stance, charging mature webtoons is also some sort of prevention because underaged people who don't have credit cards won't be able to access them.
Lezhin doesn't reduce the price or unlock any of the 19+ webtoon for free. There is exceptions to that when there's a Facebook event but even then only a few episodes are unlocked for a limited time. Of the non mature BL, 2 of them unlock chapters free, Out of Control and What Lies at the End. King's Maker was just added but free chapters might start coming after a few weeks however they don't announce which webtoons will be free beforehand. If the price of the chapters drops to 2 then 1 coin, it'll almost certainly be free. I'm not sure how Lezhin decided what webtoons will be free but How to Hate Mate, Moritat, and A Guy Like You also aren't free on the Korean site so they might not be free on the English site for the same reason.
Generally, webtoons that are free in Korean also release free chapters in English. The reverse is not always true though because a few webtoons, like Out of Control, are free in English but not in Korean.
Profitable or not the mangaka must get paid. They have sad poor lives. Drawing manga all day barely surviving.
This coming from someone who's slowly entering that territory.
it's all about money. bl sells like hot bun. you heard sex sells in bl sex sells double if not more. good for those mangaka that have such an ability and of course the readers pay.
It's come to my attention that a lot of the comics on Lezhin that aren't BL are cheaper and have a lot more free episodes.. It kind of sucks that they have the BL works at more of a premium price.. A lot of episodes for things that aren't BL are even priced as low as 1 coin. On that note, I thought I'd recommend An Uncomfortable Truth and Save Me from Lezhin, both of which aren't BL but are very interesting and have BL vibes... and have several free episodes, and many that aren't at only 1 coin.