Are you sure? I thought they were all saying it needed just a simple majority as it does with any Bill. That is +1, I didn't hear 2/3rds mentioned at all. Happy to be wrong on this.You are confused/wrong!
To call an election outside the 5 year fixed term requires, a Bill has to be raised and, to pass, that Bill requires approval of 2/3rds of eligible Members. The difference between this new one and BoJo'd previous attempt is that Corbyn has agreed, so the Bill will pass. Last time, it failed to get 2/3rds because most of Labour abstained!