Self determination is a very strong argument, you not liking it does not make it a weak one. That a country is free to decide on whatever rules it wants to, even if that means agreeing to implement some EU rules in order to trade, is extremely powerful for a nation and ingrained deep within the psyche of people - imagine if NAFTA had control of borders in North America and Mexico got to dictate US immigration policy, the US would have riots.
Some of the most famous wars in history have had self determination as a major influence in them.