“The true problem is unrestricted illegal immigration, measles is the symptom.”
I’ve yet to see any data attributing measles outbreaks to illegal immigrants. Other diseases, yes, but this measles outbreak seems to be directly traceable back to native anti-vaxxers.
If the CDC doesn't show specific traceability there is still anecdotal data from Border Patrol agents describing rashes and other diseases in children at detention centers and were directed to stop disclosing that information by their bosses..
Also, the timing seems to be more than just a coincidence.