Dont know why this is allowed.

Statistically speaking that does not seem to be true:

https://www.leagueofgraphs.com/champions/stats/draven https://www.leagueofgraphs.com/champions/stats/tristana

If you look at their game winrate/game duration you see that draven actually wins short games way more often then tristana, this is because of his strong laning phase. however if you look at his global matchups https://www.leagueofgraphs.com/champions/counters/draven tristana does seem to have a counter advantage against draven, so you might not win lane that easily.