>>96556654
because it doesn't matter. the stat line is just the stat line, and at this level of abstraction devastators putting 2 big shots down range per base is enough to make them feel mechanically distinct from a tac squad that can only do 1. any more detail would slow the game down without making it deeper or more strategic or interesting. when you can drop 60 devastators behind enemy lines and that's just one part of your overall gameplan, you don't want to get in to the minutiae of which specific heavy weapons each 5-man team is rocking.
terminators often get double heavy weps too, again it's just not worth distinguishing or having split profiles.

a lot of players have that friction when they first come over to epic because geedubs has such a good job grinding ideas like WYSIWYG and millions of little crunchy options in to players as how things "should" be. it's good to recognize that shit was standardized and put in your brain to make you buy more models. it doesn't improve games, it bogs them down. just let that shit go and learn to accept the abstractions. it makes the game better, and it will make your enjoyment of games better in general. if it's a little uncomfortable at first it's just because you're ripping a bandaid off.