well, if one love to travel and love to party I don't see in it anything wrong, actually for both I would be surprised if it's the opposite.
As for the "free" I imagine you mean: at no costs so I would just add this to the obvious:
* changing country, language, house, friends, food, etc can be fun but it requires a LOT of energy and efforts: it is an investment for yourself but with great returns for society that is (partially) covering your costs
* a student with erasmus experience is a different human being: more conscious, more able to face bureaucracy, more able to get information, more autonomous, less prone to need public funds for his professional and personal life
* any student who experience erasmus have to face being accepted as a foreigner, as somebody different, with many many prejudices ... it is not an easy experience, but it makes you more empathic on all foreigners or different humans you will meet in your life.
Traveling and living abroad is the best defense against people being used as cannon meat in wars
"politicians love to subsidies because students will be forever grateful"
what is wrong with this? what is wrong with politicians doing to citizens what makes them "to be forever grateful" ? I don't get it, do you prefer the opposite?
you correctly used "forever", and if it is a "forever" it means you have not been fooled by a politician, for a short term benefit (like receiving money).... so isn't good?
Once again your answer takes me to the concept of consciousness, meaning to know who is the cause of your problems: don't take it too personal (it applies to me, too, soooo often), but if you feel somebody else is having fun traveling and partying at EU costs, instead of asking to stop it, why don't you pretend to be in it?
I mean, even if we are not young anymore to join student parties in a cool EU dorm, can't EU money being invested in helping adults traveling and working in Europe? and having fun? and enjoy life? why not?