In children's animation there's a lot of arbitrary weird rules but among the most famous are:
* You can use lasers but not guns
* You can kill robots without problem but people are verbotom
* You can claim to send people "back into another dimension" but not kill them
* You can throw people off buildings to their obvious death but as long as they're not seen dying, you can claim otherwise
STAR WARS: REBELS creator for example claimed to Disney none of the stormtroopers that were shot in the show died, they just were knocked out due to their armor.
Different shows, different rules.
Not all animation shows geared for kids adhere to those rules.
Rick and Morty for example uses plenty of blood and gore, not to mention ballistic weapons (also, Americans are weird that they will allow kids to watch fairly violent and gory tv shows and movies thinking its all perfectly normal while being 'disgusted' at two men kissing).
Also, correct me if I'm wrong, but Lower Decks also showed people/aliens being dismembered.
And on multiple occasions we saw people actually dying (not being thrown into a different dimension).
Anyway, Trek is set in the future... energy beams are kinda a given here.