Now I supported Bernie Sanders in the primaries and I proudly support Hillary now, so I might be a little biased in saying I found this to be completely obnoxious, especially considering that there was no alternative filter of Clinton supporters.
While the average age of Twitter users is roughly 32, the large majority of snapchat users are under 30. Nearly half of all snapchat users are under 25 and another 30% are under 35. And despite being unpopular with most people in that demographic, Trump's filter actually got a lot of use.
Going back to how Clinton has struggled to win over younger voters; she has developed a reputation for desperately trying (and failing) to seem cool and relatable, which has ultimately led to people mocking her online for being out of touch. As much as millennials dislike Trump, the majority of them aren't too enthusiastic about Hillary either. More and more young voters are choosing to vote for third party candidates or just not vote at all because Hillary doesn't appeal to them like Bernie Sanders did. Bernie was an uncomplicated candidate who wanted to stand up to economic and political institutions, and Hillary crushed him in the primaries. For this reason, the simple attack on Hillary's character rather than a projection of Trump's platform was probably the most effective way to entice snapchat users to actually use the filter. Had it displayed the border wall at the bottom, it just wouldn't have been used.