In a perfectly fair system you can end up with dozens of small parties, each having small number of people in parliament, struggling to find majority for a government (see last elections in Netherlands).
That's why some voting systems are designed to give a winning party some premium over their vote percentage.
Its why NI doesn't have abortion or the same rights for Gay people its down to the Ultras in the DUP as Churchill Said "nothing so loyal as an Ulster "policeman"
Evidence for this: CSU in Germany (the quite-a-bit-more-right-wing sister party of Merkel's CDU).
Had UKIP had proportional representation in parliament their demands could be ignored forever. And while in this particular case Britain could be better off that way, it is a wrong thing to do in general.
I was strongly in favour of remain but I can see some people felt they weren't benefiting from the UK being a member of the EU. If they had been given a bit more attention early on we may not have ended up in this mess.