when you indemnify them of any consequences, that behavior gets worse and worse (i.e. "I can get away with it)
It's like a child who does something wrong and either doesn't get a real punishment or no one finds out. They will do it again.
If police officers have to self-identify, ICE should have that same rule. If they need specific warrants - ditto. It's not rocket science
And before people say "but they're being doxed" - what about Judges? They don't wear masks. There are a lot of jobs that piss people off, but they don't wear masks
ICE breaks laws every day. For example, simply swapping plates between cars, using homemade plates, or covering them is illegal and can lead to misdemeanor or felony charges, vehicle impoundment, and heavy fines.
They impersonate local police. Enter homes forcefully without a warrant (and have no responsibility to fix doors, etc., that get broken in the process).
They are also violating their own policy by conducting enforcement actions at sensitive locations, including schools, hospitals, and churches.
The mask is intimidation. It's meant to cause fear. ICE uses tactics to confuse people (10 guys on 1-2 people, all telling them different orders).
NOW - before you get on a high horse about illegal immigrants, let me say flat out that they either need a path to citizenship. Our immigration system has been broken for a long time. Mind you, having ICE show up at LEGAL proceedings where immigrants go to fulfil their obligations kinda undermines the whole "go the legal way" posture.
Obama was able to deport 3 million people without terrorizing citizens, without flash bangs, without tear gas, and WITHOUT MASKS. So, why can't this administration do so? There is absolutely no reason.
Violent raids, people simply disappearing with no way to contact their family or a lawyer, overstepping state's rights, violating court orders, weaponizing federal agencies, profiling... the list goes on and on. These actions undermine a civil society. 73% of people taken by ICE have no criminal convictions. What happened to the "worst of the worst"
Something needs to change, and fast.

