Most of these free services are ad-supported. They aren't charging you money, so you are effectively the product. The trade-off is simple: you get access to blocked content, and they get to serve you ads (or track metadata). For reading a blocked news article, the risk is negligible. For checking your bank account?
Using one is simple, but doing it safely requires a checklist. Here is the step-by-step process. website-url-unblocker
How to Unblock Websites & Access Restricted Content (13 Easy Ways) Website URL Unblockers: How They Work and Why