It was a combination of her being half british, being friendly, which some seen as overly familiar and disrespectful to her senpais and her design and overall demeanor points to her being a normie. I'm not even kidding, a portion of japanese antis seriously hates her because they felt threatened by her normie aura. Their words, not mine.
In an alternate universe the harassment would net her a 2 week suspension from the company follows by graduation citing mental reason (and luna would finally have that cruise date she thirsted for so long with matsuri), but fortunately she held on strong and her generation as well as the senpais extended a helping hand. Naturally it made the relationship with those in her circle and the hoshikuzu who supported her from the beginning more tight knitted than usual.
As for the liking porn, it was just a nontroversy. Everyone does it and admitted to it. However everyone follows everyone so they normally bookmarked the nsfw stuff, hoshikawa retweeted it and exposed her fetish (and gunkan possible bdsm history) to everyone which makes for a good laugh.