The left isn't a monolithic group, anymore than the right is. Different groups disagree (or agree) with different policies. I agree that immigration is a major issue with a lot of the left, but not the the only one.
It feels to me more like an ideology issue rather than a specific policy issue:
The left believes in a more multi-cultural country which includes Mexican, Asian, African an Islamic culture as integral parts. Trump seems to view the US as a primarily northern-European based culture which other groups are welcome to join but to which they are expected to conform.
Trump and the Republicans are very "law based". They view people here illegally as having no rights and subject to deportation in the most efficient way possible. The Left tends to think that even people here illegally should have rights and be reasonably protected from harm.
The left tends to have an overall goal if making the world a better place. The right tends to have an overall goal of making the US a better place.
Both sides tend to ignore critically important second order effects when they propose policies, and IMHO tend to have very naive views of how the world works - just in different directions.
As an example of the complexity, you can't have a long term trade imbalance because the money needs to get back to its country of origin. The real issue is when you are trading fabricated goods for permanent assets - but that is an issue in both directions. So if we have a trade imbalance with China, they ship us goods and in return invest in the US. That might sound bad for the US, and in some ways it is. OTOH, it means that WE have physical control over their assets - a rather strong bargaining chip if things get ugly. If an actual war stated, the US would immediately seize a trillion dollars worth of Chinese assets in the US.
Again, isn't the main problem with Trump is that he wants to deal with illegal immigration? Or put it another way. If he'd take illegal immigration or undocumented immigrates, however you want to term it, off the table, would the left still have as big a problem with him.
Regarding the rise in racist attacks, I haven't noticed. Perhaps its been obscured by riots, rent-a-mob, related injuries and property destruction, and the hooping and hollering by the left.