By unwelcoming NRA attendees during a convention. For reference this is the same Councileman Zach Adamson (D-17) who last year was part of a push to get the city-council to pass a law that amounted to demanding the state legislature ban all sorts of guns in Indianapolis.
It started with Zach Adamson (D-17) a grandstanding fellow who read his resolution and bragged about being in DC for a "die-in"
He did the standard litany of "weapons of war" and "designed to kill" and went with how assault weapons are specifically to mow down lots of people. But would not define /what/ caused it.
It turns out that Zach hates preemption. He railed against the statehouse taking power for itself and limited what the municipality could do.
He also went on about how congress made it legal to own "tools that can only kill mass amounts of people"
And on the "fetish with guns is out of control"
Now last year this did not even get out of committee (because 2 committee members of Zach's party did not bother to show up and thus when it went to a party-line vote it failed.
Still... the guy is very angry about Hoosiers having guns so this is not surprising at all.