These lasers are nothing more than slightly differently constructed LEDs, with collumnating lens assemblies, and special current-limiting drivers. If turning on and off the supply voltage killed them easily, they wouldn't be sold for use as laser pointers or other applications, because they would be virtually useless.
Now, if you were talking about tube lasers or other systems, that would be a different matter.
If you are still concerned about rapid switching, go out and get an el-cheapo pointer from the "dollar store" and hack it; once you have it switchable, hook it up to the Arduino and mod the blink sketch to pulse it rapidly. Leave it running for a day; is it still working? If so, you likely have your answer. If you are still concerned, then get a cheapo green module off of Ebay (one supplier I have used in the past for modules drop-ships out of china, his green 5mw modules run about $25.00 each).
Or - look into people building laser TV projectors - they use a raster scan system (essentially spinning mirrors), and then use special circuitry to vary the brightness level of the laser, which is usually one or more cheap (or not so cheap) laser pointers. Maybe they have a schematic you can use to turn the diode on, off, or anywhere in between.