The entire child crusade was caused by the Obama administration unilaterally changing asylum law to allow claims that are unrelated to a claimant's home nation state actions. Until then, being from a poor crime ridden country was not a valid ground for an asylum claim in any country. During the Obama administration, an immigration judge ruled that such a claim was valid, the Obama DOJ let the ruling stand (the DOJ can overrule immigration judges).
As soon as this policy was recognized and promoted by NGOs, the flood gates opened, women and children first instead of working adults first.
Also, until then absent congress made law for special cases, one could not travel through n-number of countries until eventually reaching the one you want to claim asylum in.
Asylum is a remedy for people in danger because of state actions or state actors -- it must be made in the first reached neutral country, not four countries over because that country has better benefits.
Trump's DOJ put things back to normal.