Even though lasers are as common as dirt now, appearing in everything from DVD players to supermarket scanners to computer mice, there's still a certain appeal to a beam of coherent, monochromatic light. Especially if it's dangerously powerful.
So it's no surprise that people can't resist playing with lasers, building their own, customizing them and, of course, setting stuff on fire with them.
Theodore Maiman probably never foresaw the ways his creation would be used when he first turned it on in 1960. But then again, he might be happy to know that someone has come up with actual laser rayguns.