Was what he was doing illegal?
Respectfully: Use your God-given brain here.
So at what point does your God-given bran tell you that someone who is open carrying is a threat as opposed to someone exercising their constitutional right?
Using your "bran", you could surmise that this perp wasn't attending a gunshow in the bathroom, wasn't preparing to hold off the Chinese People's First Route Army from seizing that grocery store, or all armed up to "protect his rights under the Second Amendment of the Constitution".
All indications are that this idiot was readying himself for some wholesale slaughter, which is all we need, isn't it?
No offense, buddy, but you wouldn't have made it past Day One in I Corps and we really don't need people like you protecting us, do we?
"Under what scenario are you carrying five firearms while wearing body armor, loading them in the stall of a grocery store bathroom?"
Was what he was doing illegal?
This one is tricky. Right now he is charged with 5 counts of Criminal Attempt to Commit a Felony. If there can be evidenced that he intended a mass shooting, by inspecting his phone and/or computer, then absolutely.
In the meantime, just like the SCOTUS judge who remarked "I cannot define obscenity, but I know it when I see it," I cannot identify the crime, but I do see the intent.
"Respectfully: Use your God-given brain here.
So at what point does your God-given bran tell you that someone who is open carrying is a threat as opposed to someone exercising their constitutional right?
Generally, my God-given brain tells me that the man is a threat when they carry 5 guns into a Publix bathroom stall, load them, and emerge wearing body armor and a ski mask.
That's a little different than the man who walks in with a single pistol on his hip.