“Why would any AMERICAN city play host to a convention of the Viva La Reconquista crowd of pro-Mexico malcontents?”
I think this is what happens when too many think the prospect of more dollars is the only worthwhile consideration.
Business setting the agenda as it too often does these days, particularly concerning illegal aliens.
“Why would the city be involved here? Is this event scheduled to be held at a city-owned venue?”
Because every city of any size aggressively pursues the convention and tourist dollars, apparently with no regard for the mission of said convention.