Per the context at the knowyourmeme link, by "very legal and very cool" I essentially mean "we've decided it's legal and now we're doing it and you might think we're full of shit but what are you going to do about it, little people?"

Cool as in "tacticool," like driving military surplus IED-hardened vehicles around for small town policing.

Or staging a shootout over property theft in an area full of civilians

or taking a guy to the hospital in chains so that doctors can spend the night inspecting the inside of his rectum and colon with increasingly invasive procedures because you think he might be hiding drugs in there

It's a Trump quote.