is having to repair the only con of getting disable ??

Few things:

1. It's often a pride thing.
2. There is a credit cost that gets pretty high later on.
3. Your combat reputation is based around your kills-disables, so those looking to get high reps avoid being disabled.

i think it's a psychological thing.... once you're disabled you're afraid people will take all your arti points....

at 200-400 aph, i was really worried about it because it takes sooooooo long to get back up to 20K points and hope for that next MSP pull

but now at 3500 aph, i'm not that concerned... 5 hours and i'm back up over 20K points..... and nowadays i curse my daily MSP because of the 20K arti point loss... (though welcome it at the same time)

can u explain to me, how do they take your artifact ??

When your disabled you can be raided. Raiding means they steal mineral points or artifact points from you.