Another factor that certainly plays a role are the social security networks in place. Europe - though not all of it - has quite the elaborate system to keep people afloat. Adding plenty of migrants into that system isn't doing much good, because most of them aren't getting into work soon, which means that not only do they not bring anything into that system, they also start as an additional burden on it. So not only do you have people who fear that migrants come to take their job or their chance at a job away (which is mostly overblown), but you also have people who now have to carry an increased burden to finance people they don't see any benefit in. People might be okay with some level of help for refugees, but when you get tons of people from places that aren't really dangerous, with people moving mostly for the economic benefit, and quite a few of those people not only not sharing the common believes of the local society but being quite a problem in their behaviour, you are bound to run into trouble. The local population isn't all that fond of people who shouldn't be there being there, with the government not being able to send them away even though their requests to stay have already been denied. It's not surprising that there are plenty of people who don't like it when the system gets played, and all the methods that exist to deal with the situation don't really work at all.
Much of this doesn't really extent to the USA, because it doesn't have anywhere near the same social security system. People who come into the country actually have to see how they finance their lives, they can't count on the state to do it for them. Of course you have people who are actively searching for jobs in both places, after all, many people don't want to be a burden on society or just need to do something to feel right. But that doesn't change the different impact on the various social systems that exist. The immigrants arriving in the US are more a felt threat to people (the worries about the job listed above, and them mostly being spanish speaking people from a different cultural background) not so much a burden on the system or the people. Unless you count the costs for incarcerating a ton of them for no good reason whatsoever, but that also applies to other parts of society (needless to say, the whole system is nuts, and the idea of private prisons as absurd as it gets).
I don't think there is all that much hypocrisy surrounding the issue, as there are quite a few important differences. Not only those mentioned above, but also the treatment in general. Those people in Europe unhappy with the migrant-wave over the last few years are mostly concerned with having control over the own borders and deciding who comes in and who gets to stay. They aren't interested in having fences or walls everywhere, nor do they think that treating people like garbage is a way to solve the situation, though a few people might think differently. That's more like the general concept that already was supposed to be in place in the US as well. Trump's government, on the other hand, isn't really doing that at all. It is going out of its way to act as a bully towards everyone, regardless of the situation. It's the difference between wanting control but keeping things humane, and wanting control in complete disregard to the people it affects. Hence it being possible for someone to be in favour of controlling immigration while being very much against the treatment shown by the current US-government.
