Even if you understand the commands, you need to trust the website because a malicious site can use JavaScript to copy something completely different into your clipboard, with a newline character at the end to automatically execute when pasted. (Is the newline exploit fixed in all shells? It used to fail in zsh but work in many others…)

One can also paste into a text editor to verify before pasting into terminal, but what noob is going to know or bother to?