I have to say itch.io is the best platform for any individual developer, but it is not safe for gamer, supporter or buyer for some condition.
Yes, when we supported the works, that means we support the developer and his/her works. But itch.io doesn't like Steam or any huge commercial game platform have strict and secure rule for preventing people who want to put some pirated or unauthorized stuffs here.
There are already many examples in tich.io before, Stardew Valley, Oneshot or other popular indie games are illegally uploaded by some gamer who bought the Drm-free version game in GOG and sold them here, even some of them are sold in the Drm version which means the games can't be played without the owner account.
I don't have screenshots of these pages but I can remember they lasted not too long, 3-4 days after I reported but they have been already supported for many dollars (you can see the contributions with the goal system)
https://chep-games.itch.io/stardew-valley (already removed)
What I want to say for the most important part for anyone who want to buy or support the games on itch.io, in the new payment rule for using Paypal to pay, the seller account which lasted 3 months can sell something that buyer can't ask refund from itch.io support but the seller. So you could have chances to get refund, but it is not 100% if the money just directly go to the seller ( I think illegal seller would indeed choose get the money through Paypal directly, not collected by itch.io and get later) But if you trust this developer so well, it is good to use credit card, there is some transaction fee to cost developer, and paying directly by credit card always can get refund if trouble comes.
Here is another example for my personal experience, I bought a bundle for some rare old games I never heard in 45 days ago, but after all I noticed that it could be illegal by someone who bought it for long time and shot a bad photo to sell these games.
After I talked to itch.io manager, he attached the seller's email that we can have the discussion, I no longer have any bad or good news, but the most striking thing is the store still keep alive, anyone could buy these sceptical things and get in danger with no refunds.
As I saw it is still online and can't be double-checked, it would be not safe for every supporter on itch.io who bought or played anything unauthorized games, even it could be dangerous to include virus or blackmail stuffs, we don't know. Honestly this is old issue, but I think itch.io should take more serious way to consider for this kind of issue, I understand itch.io is a small team, but it doesn't make sense for this reason that cause you do nothing and wait the trouble coming again. I think anyone who upload anything should be examined first by volunteer or the simple online virus detector or after reporting, please close down the page soon to check details. It doesn't need to be so hurried to get donation or support, if developers already take so much hard time on works, why we care to wait few days or a week to check right? :)
Btw, the post writing has bug, I pasted some words and links and it messed around with my finished sentence. :(