I find it hard to believe people would think earth is hollow, yet there are people who believe it. I don't brand them trolls or try to make out like they are crackpots though, because they are entitled to their (incorrect) beliefs
Why are we "entitled" to incorrect beliefs? If I chose to believe that grass was made of beef and thus all cows were cannibals would you defend my right to believe that? I hope not because it would be ridiculous! Facts are facts and our opinions don't change them!
Because nobody can tell you what to believe, that's why we are 'entitled'. People choose to research things and come to their own conclusions, it's not for someone else to tell them they should believe their opinions instead, and brand them trolls if they don't.
There is a difference between, say, believing that The Spice Girls are the greatest musical group in history and believing that the earth is flat.
It may be your opinion about the Spice Girls, I may disagree, we can discuss it but we both are entitled to an opinion about that. It is subjective.
The shape of the earth is not subjective, it is not a matter of opinion. It is what it is.
As a species we figured out that the earth is a globe thousands of years ago.
Generation after generation of scientists have reaffirmed this. We have a coherent model which matches and explains observations.
There are some debates in science, this is not one of them.
And in the last century we finally had the technology to see it for ourselves.
We now have loads of satellites in space which can take photos of the earth. We have GPS and satellite TV which demonstrably works.
We have sent quite a lot of people in space who have seen the earth as it is for themselves.
High altitude pilots can also observe the curve.
As Ricky Gervais laments in his Humanity show, it used to be "my opinion is as good as your opinion", now it seems to be "my opinion is as good as your fact".
This is obviously not true. The earth is a globe. That is not my opinion. Yes, you are entitled to a different opinion just like you're free to believe in fairies at the bottom of your garden and that the moon is made of cheese, but you ARE wrong and have been proven wrong.
If you want to put your fingers in your ears and go "la la la, can't hear you" and ignore the mountain of evidence proving you wrong then there's nothing I can do about that, but don't go around pretending that this is just a matter of opinion and that all opinions about this are equally valid.