It's interesting as unlimited migration as permitted within the EU had both advantages and disadvantages, of course. Some people felt, justifiably or unjustifiably, that their share of the pie would reduce (i.e. regarding jobs, state benefits etc) but others will be aware of staff shortages that may now occur in various industries. An unfair stereotype and mentioned merely for the point of amusement would be an old person voting for Brexit not realising that their carers may soon be in short supply (although it could be argued that we should train our own people and they should be more highly valued by society in general and pay them a more competitive wage).
I am very pro-European myself and did not vote for Brexit but I do recognise that certain communities feel swamped by immigrants from elsewhere in the EU. In fact, last night I was informed by a German friend of mine that his local (and which used to be mine), which is in a rural town in Germany but on the Dutch border, has been taken over by Polish management, sells Polish beer and now had predominantly Polish clientele. Such an anecdote proves very little in itself but the nature of society changing so rapidly (and one in five German residents are now first or second generation immigrants) does make some people feel disenfranchised and/or disadvantaged.