This is probably a bit too cynical; it's not just "politicians who want to be seen doing something"; the public often wants something done as well. And "we didn't do anything after that incident from ten years ago and now it happened again" is not a good look. Complex stories about trade-offs and the cure being worse than the disease often don't "play well" in the media, especially not with the opposition demanding that "something could have been done!" And corporations tend to be pathologically risk-averse.
Politicians, the media, corporations, and the public all have a part in this.
Sure, that's why the politicians want to be seen doing it. But the legislative focus is often on getting something passed now while it's a hot issue rather than on eventually getting a good bill passed (let alone deciding that we actually already have the correct amount of legislation on the topic).
Politicians, the media, corporations, and the public all have a part in this.