It's impossible to answer every single crackpot all the time
Yes, and it is a problem. How do you know that they are wrong?
You don't, the problem is that you cannot investigate every wild claim.
And in some cases, it isn't even possible to test those claims at which point there is literally no way to know if they are right or wrong.
In other cases it is merely impossible for one of the options, i.e. some experiments could show they are likely right, but no way to show they are wrong; or some could show they are wrong, with none being able to show they are right.
For example, what if someone said magnetism is explained by magic pixies, where pixies reside in the poles of magnets and fly out and try to pull things they like into the magnet and push things they don't like away from it.
This is pretty much impossible to test.
So instead of trying to entertain everything and getting nothing done, you prioritise.
Imagine if they said that to Einstein back in 1910's
The distinction was the Einstein could show a fundamental problem, a contradiction in the current understanding that needed something to resolve it.
In the then current understanding, if an object B travels at some velocity v relative to a stationary observer A, and throws an object C at a velocity of u relative to them, then relative to the observer A, the object C will be travelling at a velocity of v+u.
In addition, the speed of light in a vacuum is c, regardless of observer.
So now what happens if the object C is a photon of light?
Then we have v + c = c, which is impossible.
The basic math of Newtonian relativity says that speed of the photon should be faster than the speed of light, by whatever velocity B is travelling at.
Conversely, observations show that the speed of light must be c.
You could attempt to explain away these observations with the aether model, but then the speed of light is only constant relative to the aether, which still doesn't match reality.
So an alternative is needed.
SR is this alternative.
As for GR, a standing problem was why the gravitational mass was the inertial mass.
i.e. why, unlike the other forces, gravity used mass instead of some gravitational charge or the like.
Why unlike other forces, an object in a gravitational field will accelerate the same, regardless of what its mass is.
GR with curved space time can explain that.
The other thing it explained was the precession of mercury which did not match that expected for F=GMm/r^2.
And even with all that, there was still a lot of skepticism.
Even Einstein himself disliked a fundamental aspect of quantum mechanics which he helped establish, the apparent randomness of nature.