Florida's age increase of 18 to 21 for ammo and long guns was indeed a response to Parkland, but does it really matter in this particular case? It also applies to all vendors of firearms in the state of Florida, not just Dick's. Anyone under 21 can still use a firearm if under supervision of someone 21 and older. It does help stem edgy teens from just buying one and shooting up a school(not that they can't steal one, but).
I'm totally pro-gun but I'd say that this isn't an unreasonable change. And those saying it's "unconstitutional" are delusional. Those under 21 can still obtain access to firearms to go hunting or a shooting range or whatever. They just can't own it yet. Considering handguns and CWL are age 21+, this is just making the law involving guns more uniform. Handguns were originally 21+ versus long guns due to their concealable nature. Given that teens can be unstable and aren't able to obtain proper healthcare(maybe some day?), this is a reasonable course of action that hardly conflicts with our rights to bear arms. This change really does almost nothing to your average joe. You can still get your 19 year old or whatever a gun but he just can't "buy it" yet. If people blow their shit over something as docile and reasonable as this, it just makes the gun community look bad. It's not like they're raising the total age to 25 or something. Or saying no hollow points. Or no pistol grips. Etc.
Dick's is indeed being a total cuck by removing AR's and such from their stores though.