Is it because we have an entire generation whose conception of sex and sexuality have been solely informed by badly translated Japanese hentai?
Whenever I hear "lewd" I imagine crusty old ladies at a parish bridge club voicing their disapproval of poodle skirts or something
has it though? where are you seeing this increased usage? I checked google analytics and it does show a steady increase <see here> so maybe you're right, but it's still pretty subtle. I think this might be endemic to whatever content you're looking at tbh
edit: localizing the data to canada or the usa flattens the graph even more, look at the past 5 years or past year for the usa in trends and it's very stable