At the end of the day, you go to whomever offers you a contract I suppose.
There's lots of instances of someone growing up supporting one club and then playing for that clubs rivals. Carragher got most of the stick he got for the way he went about it (Same with Gerrard)
There's been other cases of childhood blues going to Liverpool and they've never received more than a bit of banter.
It's how you carry yourself and the way you behave.
If I was a professional footballer and the only offer on the table was Liverpool, then I'd consider it. But I'd still be respectful of the Everton fans and would be fully aware that I was going to get some stick when I played in the Derby
Ideally, there'd be another offer on the table. I'd play in a lower league than for Liverpool because, if I was godo enough, there's always a chance another Premiership side would want me.
If it's a choice between Liverpool and Stoke for instance, I'd pick Stoke just to avoid the hassle