"It's losing its meaning," Westwood said. "It's social media, not social slagging. It seems to have turned into that for some people."
Flamboyant Englishman Ian Poulter, who will play Westwood in the final 16 of the World Match Play Championship in Spain on Saturday, has been the target of heavy criticism on Twitter, while 1999 British Open champion Paul Lawrie has closed his account.
England soccer star Wayne Rooney recently joined Twitter and this week threatened to put a user "to sleep in 10 seconds" after being sent abusive messages.
"It's just pathetic," Westwood said. "It's there to interact with people and give them an idea of stuff they might not ordinarily be able to engage with. But some always take it too far and spoil it."
Second-ranked Luke Donald said the "negative media" toward Poulter was frustrating, but Donald intended to continue tweeting.
"That's not the tool it was meant for ... but it hasn't got to that point for me yet," Donald said.
Graeme McDowell, the fifth-ranked Northern Ireland player, said Twitter abuse "goes with the territory."
"People open an account and all they want to do is abuse celebrities and sportsmen to try to get a response," McDowell said. "You try not to encourage them, and generally I just block them, but if you want to stay on it you're going to have to accept some absolute trash that people talk.
"It's downright evil, some of the stuff."
Westwood and Poulter often exchange messages over Twitter to rile up each other, but the top-ranked player said that wouldn't be happening before their match on Saturday.