In my opinion, the Airlines don't all hate single pilot operation but some individual who work for them (and sometimes do the recruitment) who really have no idea of what they are talking about.
By that I mean they have never done it, as simple as that. Oh yeah, they have read about it or heard stories which gave them only enough knowledge to form an ill informed opinion and usually, an ever lasting one.
Single pilot operation can be very demanding but what makes the difference is who you operate for. i.e are they ready to put up the money on maintenance, training etc...
Lots of guys who now fly for the airlines (and some reputable ones), come from GA and have flown single pilot. No regret there for me, all great stuff.