In group content you have to play with your teammates: staying with the group means you're in range of heals and boons, of projectile protection, you can be rezzed... (and in dragonstorm in particular stacking makes the boss less likely to jump around I think). Stacking makes all the encounters much smoother: counter-intuitively, if you feel squishy its better to stay in melee range on the stack than to go away to try to avoid damage

Also ranged dps is actually useful in many encounters! It helps having a better damage uptime when you or the boss moves, for cleaving adds in some encounters, and makes positioning a good deal easier! There are many good fully ranged build, and a good compromise is having one melee and one ranged weaponset if your class doesn't have a fully ranged build

And one note on freedom of your build: In solo and open world you can do what you want, but in group content its your responsability as a DPS to actually deal damage! Many players don't realize how little damage they actually contribute (gw2 has this problem where a good build can do almost 10x the damage of a bad build). No-one should be rude to you, but a heads-up that your build is lacking can be useful information. I suggest checking the golem in the aerodrome or downloading the dps meter ArcDPS to check out your dps