Okay, so clearly they weren't deployed "to protect constitutional rights" considering ICE was violating the 1st, 4th, 5th, and 14th Amendments and the military was illegally deployed to ensure said violations continued so that argument's non-starter.
What's left... "So like when ICE was being harassed in L.A."
Exercising the First Amendment right to Free Speech in protest isn't harrassent so that's out the window. Additionally, any assaults, interferences committed against ICE agents are arrestable offenses, with said arrests being legally executable by, a job for ICE or the local constabulary. If such occurred, ICE would have arrested those individuals. And before you start making noises about "they were keeping ICE from doing its job," ICE's warrantless, illegal arrests (reads as "kidnapping") continued unabated during the protests which allegedly required military deployment sooo... oops.
"When Portland police refuse to assist ICE."
Local police are neither under legal obligation to assist federal officers in their duties nor does said non-assistance constitute "interference". And, as you argument hinges on federal officers carrying out *lawful* duties and ICE's actions are being carried out in violation of multiple Constitutional Amendments, said actions are unlawful and, therefore, criminal - thus rendering invocation of the Insurrection Act unlawful, military servicemembers acting under orders in said same in violation of 10 USC 892: Art. 92's implicit duty to disobey unlawful orders.
"When any sanctuary city refuses to assist ICE in their lawful orders to remove criminal migrants."
Just as with local & state police, local officials are also under no legal obligation to assist federal officers in their duties... and ICE continues to carry out warrantless, illegal arrests in sanctuary cities without the assistance of the military. Triple oops.
In case you haven't figured it out yet, the fact that ICE's warrantless, illegal arrests continued unabated during the protests means there was no failure of ICE to carry out its orders, thus invocation of the Insurrection Act was unlawful -making the deployment of the National Guard and U.S. military on the streets of L.A., Portland illegal.
Also, Portland isn't a war zone as even the most cursory check of its multitude of traffic cams will immediately and consistently demonstrate. Sooo... just thought I'd throw that out there.