When is it okay for a Pokemon to NOT run a STAB move in Competitive Battling?

Title question should say it all. Take a look at this set:

Porygon2 @ EvioliteAbility: TraceEVs: 252 HP / 4 SpA / 252 SpDCalm NatureIVs: 0 Atk- Ice Beam- Toxic- Recover- Teleport

Back when Porygon2 was in NU, (it’s in RU atm) I would usually see this set. As you can see, the attacking move isn’t a STAB move. Why is that? When is okay for a Pokemon to not run a STAB move?

Pleaselog inorregisterto add a comment.

When it doesn’t need to attack or its offensive stats will just tickle the enemy. This means that it is usually dedicated support Pokemon. The most perfect example is Blissey. As far as I know since its existence, it never ran a normal type stab move and usually went with seismic toss. Even now in gen eight it runs shadow ball over anything else. Another good example was a Skarmory variant in gen six with spikes, roost, defog and whirlwind so it has flexibility on how it wants to annoy the enemy. Some more example is Garchomp and Hydreigon in current gen eight. It’s not always but sometimes, sd Garchomp goes rocks edgequake or edgequake fire blast while Hydreigon usually goes support with defog roost epower and dark pulse

All in all, when a Pokemon’s job is not to attack, has a specific target, has a colorful movepool or is a dragon type, then it can afford to skip its stab. Your Porygon example is one I assume to hit dog Zygarde since Porygon is so bulky. As for the dragon type, dragon claw and outrage are no longer as good. Dclaw would sometimes fall short while outrage is a death sentence so most physical dragon types sometimes skip one of its stabs

It might be ok to have no STAB moves when you need status moves or more coverage.

STAB isn’t always nessecary. (Ik I spelled that wrong).

You might choose to have a staller that is bulky and not meant for hitting at all, and you might need a lot of coverage for another Pokémon, taking out it’s STAB moves, which isn’t always too bad.