Because only people who matter get harassed. She thinks she's important enough to have attracted notice - and to be fair, she does have a thread here. But we're hands-off, and eminently ignorable; the only attention she's ever gotten in the wider world is a couple of her tweets getting mocked and the anonymous contribution to the Kotaku article about Riot that she immediately took credit for.Why would anyone go to the trouble of harassing her specifically?
She also loudly proclaims herself to be a member of enough groups that are presumed to get harassed online simply for existing, being a woman, non-binary, trans, jewish, a female-presenting gamer and nerd, latina/o/x, etc. She could have been satisfied with just being 'woman who worked for gaming company = instant online harassment', something her orbiters wholeheartedly believe and isn't even a complete falsehood, but she has to pile on the identities, and therefore the reasons for being harassed, until her every waking moment online involves someone emailing or DMing her mean things.
Which is something she seems completely incapable of doing anything about using the numerous tools available to her. Because again, her and her followers believe that there's millions of alt-right gamergater trolls who devote their life to creating socks and evading bans just to tell them they suck, so why bother turning off DMs or installing email filters?