Do you think that foreigners should be allowed to enter USA illegally and to stay here?
No.
Irrelevant to the issue. Tancredo is not only against illegal immigration. He favors greatly restricting legal immigration as well, and calls all proposals for cutting back on illegal immigration, but allowing for more legal immigration 'Amnesty'.
What the underline crime is for which 'Amnesty' needs to be granted in that particular circumstance, is unclear. I can only assume he thinks they need to be forgiven for being born in another country.