i think you are using a single example to cast judgment on a whole genre, with is not really fair. while YA does have a lot of romance, this is the case of 'all squares are rectangles but not all rectangles are squares'.

your romance example is also not limited to YA, or space fiction. i am currently reading a fantasy adult novel and the number of times i have rolled my eyes over the romance relationships are giving me eyestrain.

so i think if you were to re-frame the discussion as more of 'this is a trope i do not like in a genre i otherwise enjoy' you would get more interaction. rather than the 'don't like it, don't read it' reaction.