One thing about a world with literally billions of smart people looking for solutions to problems is that any simple idea you have for something that is not in use very probably doesn't work. If it did it would be in use already.
This is a common mistake in using probabilistics for arguments.
This probability is the same for everybody. If we accept the policy of not announcing an idea, because it’s almost certain somebody else tried it, there is a problem. There must be a person, who is the first person with the idea. But for them this probability is also the same. Therefore — by policy — they should not reveal the idea. And the same applies to everybody after them. Which leads to a situation, where the idea is never announced. Which contradicts the initial condition of this probability being non-zero.
Other than leading to this conflict, this way of interpreting the probability leads to more serious trouble. The more people involved in an event, the more likely is that each of them will assume somebody else already took some required action. But since everybody assumes this, in the end the chances of anybody taking action gets close to zero.
The right interpretation is different. The high chance of somebody else already announcing the idea (or making a software bug report, or calling for help, …) should rather lead to verification. For example by searching for similar ideas being already proposed (or bugs reported, or help called for, …). Which is exactly what OP did above: seeked opinions of others. There is absolutely no reason to shame them or otherwise give neegative feedback on the behavior itself.
Pedants disclaimer: I’m aware this probability is a function of time (hence not identical to everybody), that the set of people with the idea is not strictly speaking a totally ordered set, that I mix “got idea” and “announced idea” for clearer description, and that this is better described as a case of failing to update the model after changing policies.