He doesn't know.
Because he doesn't care.
When considering new players, I find it difficult to attribute not knowing to not caring. This is especially true since so much of the education surrounding gameplay is inherently community-taught with no supporting game mechanics to provide structure for it. They only learn what they absorb from others, and that's such a squishy social variable that it's guaranteed that some will go about it civilly, and others /destructively/.
From a new player's perspective - and especially using other games as a means of (inaccurate) comparison - the gunner role seems to be the one that commands the most importance. If their (incorrect) understanding is that a vessel's chief effectiveness comes from those operating the armament, then the theory may assemble that the engineer is a dedicated "medic" that exclusively maintains the remaining operations. This is not a lack of /caring/, this is a misapplication of /logic/. If players are given free reign to choose whichever class they choose on joining, why couldn't this be the case?
A second gunner receiving flak for choosing that class may observe engineer as a demotion - "you're not allowed to shoot until you're actually good" - or even pressure into a role they don't believe they can handle yet.
This is why rigid game mechanics are so important. A cap on gunner joins communicates a paradigm that engineers are the "default" crew role, and that they are as functional (and important!) in offensive strategy as the rest of the crew. As well, it 100% prevents the genuine accidental join from a player that isn't versed enough to double-check their class before joining an empty slot.
This is not to discredit situations where a new gunner is purposefully being abrasive or denying advice from other players, but I believe that a lot of this behavior stems from a misunderstanding about important game mechanics that are not reinforced /anywhere/ in the architecture of the game itself. Hence why it's such a heated social situation whenever it crops up.
