So the Internet is being bombarded lately with a relatively new phenomenon. Whenever a mass-killing takes place (which are happening with greater and greater frequency); there are numerous blogs and vlogs appearing alleging that the whole incident was staged. Despite the sheer impossibility of such a hoax, people are apparently buying into some of this.
Basically, the reason for this phenomenon is twofold. One is the Mainstream Media's incompetent reporting and the other is the Mainstream Media's overt anti-2nd Amendment propaganda. These two factors give the illusion of a conspiracy. In reality, though, the Media and vested financial/political interests are simply following the maxim laid down by 1960's rabble-rouser Saul Alinsky, who said "Never let a good crisis go to waste."
In other words, the conspiracy theorists correctly see through the phoniness of media coverage in places like Parkland; but they commit the logical error of assuming that those exploiting a tragedy necessarily must have orchestrated it. This is a common fallacy in American discourse today.
Most people in law enforcement understand that the greater and larger a criminal conspiracy is, the more likely it is that conspiracy will be compromised. To quote another old maxim---this one from Ben Franklin---"two can keep a secret if one of them is dead." The kind of money and logistical support that gun-grabbers would have to expend to stage an incident like Parkland would be even harder than---as some others allege---staging the Moon landings. Those groups would be better served using funds and actors to elect politicians in sympathy with their views than engaging in a false-flag operation which stands an extremely high probability of being exposed.
Consider also that Parkland is less than an hour's drive from Miami---home to an FBI field-office. It's also less than an hour's drive from the Trump Estate at Mar-a-Lago, where there is a Secret Service headquarters. These agencies no doubt investigated Parkland; if it were a hoax, they'd have exposed it immediately.
Don't buy into this tinfoil-hat nonsense. It doesn't help the pro-2nd Amendment cause in the least and gives ammunition (no pun intended) to its foes.