Why trump wants to deport millions of inmigrants?

To answer this question, we have to look at Trump's website where he expounds on his policy and rhetoric. Though he has spoken with various degrees of certainty on the subject Trump's official statement is this, " Anyone who enters the U.S. illegally is subject to deportation. That is what it means to have laws and to have a country." This is not calling for the deportation of millions rather stating that if you enter the country illegally and do not pay taxes, you are not a citizen. Regardless of my personal thoughts on this subject, the reasoning is quite simple. President Trump believes it is unfair that those who enter the country illegally and do not pay taxes use systems such as healthcare and the public school system. This, of course, arises many moral questions and if you are curious for more expansion on that, please message me more comment.