Like someone said earlier, let's compare apples to apples. Try not to go off on a tangent and take a 'good' local vs a 'bad' foreign. Skewed comparisons work the other way as well.

If 2 candidates were absolutely identical in terms of their personal traits, just that one had a local degree and the other a foreign degree - then it's inevitable that the foreign degree holder has an advantage. It might be large or small, but it's an advantage nonetheless. And most times, when bosses can't make up their mind between 2 candidates' skills and personalities, the better recognised qualification will tip the scales. Easily justifiable within an objective assessment system.

Foreign universities has better overall education packages. The education system has provided intuitsive learning environment because if you are a overseas grad, you'll be expose to many people from different ethnics and groups. Therefore the chances of interacting with these professionals helps the invidual to develop strong communication skills and becomes more approachable. I'm from local uni and I dun get the necessary 'people' to communicate. I tend to stick to the same 'gang' while doing my studies. Hence I believe foreign grads have better opportunity when comes to securing a job. Chances of doing well in interview sessions are better than local grads.