It's a reasonable question, and it's unfortunate that he went on such a long rant instead of asking a concise question.
Whom illegal immigrants are competing with over low-skilled jobs is irrelevant to the point I think he was trying to make, which is ... from a conservative or libertarian perspective, why should one have an issue with illegals performing these jobs when the result, economically speaking, is a net benefit overall for most people? The owner, by paying lower wages, can pass on those savings to consumers, and charge less for goods and services, right? Or am I missing something?
And if you argue that hiring illegals is against the law, and we don't want to encourage law breaking, wouldn't going after owners who hire illegals be more cost effective than walls on the southern border ... especially considering most of those who come to this country aren't merely strolling across the border? Isn't there some policy we could implement to incentivize self-deportation?