Greta, it only makes a difference because if we are celebrating that 1 million marched, if 500,000 were say, 5 year old, you could not really count them because they have no idea about it and if there was another vote, their views would not be heard. That was an extreme example but you get my drift.
I don't think all EU nationals should have been allowed to vote but I do agree that EU nationals who have been UK resident and worked for a given number of years or have married a Brit should have had a say. It is a difficult one to decide what the cut off point should be but I would not consider I was "invested" in a country just because I worked in it. Given time, that might change but it wouldn't be an immediate thing. Also, a lot of those who work over here absolutely don't intend to stay forever so I am not sure of the legitimacy of wanting to vote in this country's future.
I have 2 friends who have been in this country for the last 20 years and the last thing I want to do is make them feel unwelcome or unloved. However, that does not mean I want to stay in the EU as it currently stands and that has nothing to do with the way I feel about them.