Er, have you read the Reuters link?
"The GSMA mobile operators' trade association refused to comment on a Reuters report that later this month it will propose an emergency meeting to impose a de facto ban on the use of Huawei equipment by its members."
Perhaps because that's not what the Reuters report says? GSMA doesn't have the authority to ban anything. The report was suggesting they might discuss a response to government bans.
(Given that the big three Chinese operators are all GSMA members, it would be interesting to see what response they come up with!)