The worst part of low-timers at an airline is that when they upgrade, the STILL don't have the practice making decisions. But now they are in charge of their duties, the duties of the FO, the FA, and the entire aircraft. The scope of the responsibility just increased exponentially, and these decisions must be made real world, real time, live without a net. You won't even understand why this is a big deal until you actually do it for awhile.
Put in a couple of years in the right seat, get your upgrade, and you will learn a whole new world all over again. And you will FEAR flying with a low-time pilot in a challenging situation because it's like flying single pilot with a constant distraction - even if the guy has been trained from the best.
Nothing against low timers - it's not your fault that you get hired too soon. But you are too green for the job, and that's just the way it is, college / ab-initio guys. I know, because I was one of you and I am telling y'all that 250 hours and your ratings is just the start.
Some claim that because there are lousy high-time pilots, that must correlate somehow to the number of incompetent low-timers, too. Couldn't be any worse logic - SOME high timers can't cut it because they are in the wrong line of work. But NO low timers can be considered full pilots until they get some practice making decisions.
Blame the airlines, and the airlines alone, for the fact that low timers get hired. But if you're lucky enough to get hired early, just try to listen to your captains as much as you can. Good luck!