"Enforce the law" means deporting people here illegally, and since there's masses of people here illegally, it would mean mass deportations.
Trump wants to make it possible for illegals to stay at the expense of American citizens and of those who try becoming American citizens by the law.
Ergo Trumps supporters want to make it possible for illegals to stay at the expense of American citizens and of those who try becoming American citizens by the law.
They are empowering illegals to stay. They are pro illegal. Period.