Most of the conventional press is new to the moba genre. The international got a new swell of people interested in it, including journalists, and Dota is the newer one. Its not as popular as League, but it is still bat shit crazy popular, and it has the reputation of being a harder game to master, so it kind of seems natural to start there if you are knew to the genre.
You know each game will take hundreds of hours to "master", so yeah it seems logical to start with the one that will take you farther and potentially be around longer.
There's a guy in my college that doesn't drink but when ever we decide to go out, like all planning on getting proper messed up, he insists on coming and it is so annoying when he just sits around not drinking, he doesn't even get a coke.