My partner is EE and only lives in the UK because of me, we met in Canada. In Canada and South America where he previously lived he was treated as a European, in the UK he often is treated as an Eastern European. Like you say different to if he were French or Scandinavian, but he is Croatian which I think is considered 'better' because it's a nice holiday destination and they did a good job of renaming/branding the country from Hrvatska.
He hasn't had any issues in the street but at work his boss appreciates him for being a 'good worker' but thinks of him as an uneducated idiot. For example he was shocked that he could calculate VAT and then when my partner said yes I have a degree in economy and ran my own business! He also employees a Serbian girl and they are both paid half as much as the posh English girl and guy that he hired since.
Anyway now the stuff I needed to do in the UK is sorted, we are going back to Canada!
In regards to 'economic migrants' every immigrant even 'ex-pats' are! When I am in Canada I am an economic migrant (I get paid more relative to living costs). My Mum, her brother and two sisters are all economic migrants because they live in Spain, Portugal and Thailand for a lower cost of living to eek out their pensions. Many French come to London to make big bucks in The City. Everyone goes somewhere for a reason, and that doesn't make them 'the wrong sort of migrant'.
Secondly, knowing many EE through my partner, people do not just move to the UK for better wages (which are often eaten up by higher costs) they do so because it is considered a fairer and less corrupt society. But many when they get here are treated differently and go back. Also it costs a lot of money to move to the UK (travel, rent, deposit etc.) which they bring from EE and spend in the UK. It is the middle class well educated who can afford too, 'the cream' as the Polish PM said, not that this should matter but it does surprise a lot of English people that consider anyone who move country to be desperate.
Overall OP before I met my partner I had a lot of respect for EE's, but since I have a real appreciation. I find Croatians and Romanians (who I work with) to be far more easy and fun to socialise and make friends with then a lot of English: outgoing, warm, friendly, generous, hospitable, and a very dark naughty humour. You can meet someone once, and get an invite to stay with them a week later.
P.S. If you fancy a night off from assimilating and are in or near London I thoroughly recommend the Borsch comedy night in Camden once such things are back up and running.