1 - They did not vote to join the EU, they voted to join the pre-cursor of the EEC and as such the slow amalgamation into being forced to be part of the EU was not democratic, because there was no vote to merge.
I really get fed up with this mardy, "we didn't vote for it" nonsense. We have a Parliamentary democracy, not one of plebiscite. Ted Heath was elected in 1970 and it was known that he wanted to take us in. So if they voted Tory, that is what they voted for. They then didn't vote to go in, in 1975, already being in - that was Harold Wilson pulling the same stunt as Cameron, but Wilson was a sight more crafty than Cameron, so got the result he wanted.
2 - It is not economically viable for Germany, UK and to some extent france, to prop up failing economies of Europe. (especially the later joining states, which again the UK people did not vote for).
Again this is rubbish - Major pressed for the inclusion of the E European states. Major was re-elected in 1992 with a majority, so the same comments about 'not voting for it' apply.
3 - The misuse and abuse of foreign labour. - People coming across for seasonal work (for example farming) where they just come over here for a few months, are treated badly by the employer (basically gang labour) and then sent back home is not embracing foreigners in the country.
Then they need to take that up with UK employers and UK Governments. Shitty employers will probably always exist, certainly as long as they can get away with it. The Chinese cockle pickers who drowned in Morecambe Bay weren't EU citizens, but you can bet the employer was a shit to let it happen.