Why should those who were here illegally—especially given their overwhelmingly low-skill status—be allowed to apply to return legally? Current law would not allow that, and given how many more capable applicants we have, I see no reason to overlook their crimes.
That is an excellent question, and I have mixed feelings. My reasons are mainly practical.
(1) Whatever number of immigrants Congress chooses to allow, those who have been here without using government benefits are already in a sense vetted for character and productivity; those are better immigrants to take, assuming they meet the skill restriction that Congress should be setting.
and
(2) It seems more humane and compassionate to chase ALL illegals out if those who played by the rules have a chance to come back. We're more likely to get ALL of them self-deporting, which is a whole lot cheaper than paying for it.
For those benefits, I'm willing to compromise on what may be a small number of criminals allowed back in legally. It may not be the exact right answer morally, but the outcome is likely to be much better for America than any other plan I can imagine implementing. [Just screen them for all crimes including identity theft and illegal voting while here, and do not allow ANY who committed such crimes to return]