@migh
"the MC isnt even portayed as a shitty brat in this manga"
Does he need to be? I know rape is bad. No, I doubt 99.99% of people reading this aren't suddenly compelled to roofie up someone because there wasn't a huge disclaimer bashing them on the head (and lets face it: those 0.01% fucked up to do it aren't going to care about a disclaimer).
"is it just me or the amount of rape and sexual contents highly increased in manga these past years ?"
80% you. You're more conscious of it so you're more aware of when it pops up than years ago. therefore to you, it seems it's "happening more often". Classic Baader-Meinhof phenomenon (also simply called "frequency illusion")
20% the fact that (I imagine, would need to research to back this up) more and more manga is being translated than even 5 years ago. So there may in fact be more content to choose from in English than before. But that's not a phenomenon exclusive only to themes of sexual violence. I'd wager the gap between action manga and everything else increased over the years.