They mean different things, hence why they're different things, now that may be different from your perspective, but for most its not.
You could say a handshake means you're laughing in there face, while that seems like an extreme example; From someones perspective that could be the case that they think its laughing in there face but for most its not so we go with the majority.
For the majority of people I'd assume based off my experiences when they pump there fist in the air its when they scored a goal as a victory salute for themselves rather then showing off to the enemy team vs when your laughing and dancing in there face because your scored a goal/won comes off more as disrespectful.
I'm not setting lines I'm just saying how people perceive such actions, while it is subjective, the majority, from my experiences, and others; Perceive those actions as such.
Its not okay, from my point of a view and I'd say for most peoples, its rude and disrespectful to showboat with the intent of making the enemy feel worse.