And that is still awful but for other people. Vector is a commonly used term in tech. If you lookup for help about using (mathematical) vector you'll now have to narrow the search using other tag otherwise you gonna get spammed with marketing crap about that technology.
Even if the Deciders called it Vector.im or Vector Messenger, and did some SEO, it wouldn't be that hard to find.
In fact Riot.im shows up at #8 on DDG and #6 on Google (for me) when "riot" is searched, even when "riot" is a very hyped up search term. (https://trends.google.com/trends/explore?q=riot)