It’s not, but sneaking into a country is different than walking into a border checkpoint or embassy to request asylum.
https://www.law.cornell.edu/uscode/text/8/1158
> Any alien who is physically present in the United States or who arrives in the United States (whether or not at a designated port of arrival and including an alien who is brought to the United States after having been interdicted in international or United States waters), irrespective of such alien’s status, may apply for asylum in accordance with this section...
In this case the Atty General could claim that it is in the public interest to take in every unaccompanied alien child (defined as such by law [1]) - however that means that every child would basically go to the foster system while their parents were deported. Perhaps that is what is happening, I'm not sure.
In either case, the unaccompanied child and the adult in this case have different processes that the DOJ and in the case of children Health and Human Services, have guidelines to follow.
Which is slightly different, but none the less alternative legal means.