That is fine..... See you in the next one. Hope you see how the burden of prof is not my own now. Latters.
Let's say you want to find out if a Chupacabra is real. So, you go out to where they have supposedly been spotted, looking for one.
While out looking for one, you hear all manner of accounts. Some claim the creature is 6 feet tall, glowing red eyes, walks on two legs, can fly. Others say it's a small rat like looking creature, hairless, etc. Some claim to know it's nothing more than a coyote with mange, or a raccoon with mange. Others claim it's a government tested animal escaped from some lab. Still others claim it's a supernatural interdimensional being, or perhaps an extraterrestrial.
You look at video footage some have gotten, you manage to find some fresh animal carrion that is attributed to a Chupacabra, you hear accounts, so on and so forth. And let's say you even see a creature one day run across a rural road, that you cannot identify, although it doesn't defy the animal kingdom as you know it (IOW it's not a 7 foot tall, glowing red eyes man-goat with wings) rather let's say it just doesn't look quite like anything you've seen before ... say a cross between a hairless hyena and a small kangaroo or something ... and the first time you see it you think, "Holy wow, is that a Chupacabra ?"
So now you have evidence of
something ... dead animals, video, eye witnesses, and you/yourself saw something as well that was hard to identify.
After looking at it all ... can you now say definitively what a Chupacabra is or isn't ? If you decide to go with "coyote with mange" which is a popular theory and seemingly backed by lots of evidence, how can you disprove that there isn't a 7 foot tall bipedal goat sucking bat-humanoid with wings and glowing red eyes killing livestock ? How can you prove that there isn't a supernatural being involved in some of the other cases ? Or even more mundanely but still unique, what if there are multiple normal animals (coyotes, raccoons, wolverines, etc) running around with mange and it's an odd coincidence that these different animals have mange and are being sighted at the same time ?
What helps someone back up their assertions, are evidence. Eye-witness accounts are generally very unreliable, which is why corroborating evidence helps to determine the facts of what was seen and not seen. Even an eye-witness who saw an actual something may get details wrong, or think something is happening that isn't even happening or take place. Now, if a person were interested to the degree they wanted to investigate someone's account and claim ... okay. And what you are basically pointing out, is that, "If you really wanted to know this, you would investigate. It's not up to me to prove what I'm saying is true, it's up to you to find out if what I'm saying is true for yourself."
But consider the Chupacabra example ... even someone who is investigating such accounts will run into a plethora of different claims, explanations, theories, etc. What happens when the evidence they find points to your own claims being wrong ? What if they find a much more mundane explanation ? What if they find nothing at all ? Or what if they conclude something spectacular that even seems more extraordinary then your own claim ? In general, if you want your claim to be taken seriously, there should be evidence to back it up. Otherwise, you are often just one of many voices saying, "I know the truth !" with little more than words for all we know.
Now consider one more thing: suppose you actually did see, 100%, something extraordinary. Let's say you saw a 7 foot tall flying humanoid with glowing red eyes sucking blood out of a goat, then it takes off into the night and disappears in a puff of flame or some such. And let's say this ACTUALLY happened. But you have no video evidence of it, nothing to corroborate your story. Let's say for a moment that the carcass even went up in a puff of smoke, leaving no trace behind.
Even if this happened in reality, how would you convince someone else ? And for what practical reason would it matter to them ? Let's say they even went looking for it, based on your account and nothing more than your word ... but found nothing, saw nothing, etc. At what point for practical purposes, would such a person be able to say, "Well, I can't prove you wrong, but you've got nothing to show for your story, I found nothing when I investigated, so even if you're right it's basically meaningless to me because recognizing whether you're right or wrong is irrelevant to my own experience." Burden of proof is more than just intellectual honesty, or one person thinking the other is lazy ... there are often a sea of claims and explanations and speculations for the same thing, which people often DO investigate and do not find what is claimed to be found, and at some point draw different conclusions than what you may have drawn. Or, they have decided to stop trying to figure something out, and wait and see if anyone who is making claims can back up their claim with evidence. This isn't always due to "I don't care anymore,", rather this can often just cut through the myriad of voices and begin to see who may actually have something substantial to offer.