This is not and has never been safe.
It's just the plausible blame that shifts.
If you read the script before you pipe it into your shell, it's safe.
And if that's not safe, then it's just as dangerous to trust that an unopened bottle of ketchup is safe.
Nothing is safe. Everything is a judgement. Being culpable is a professional service. Lucky people out-earn unlucky people. The world is a scary place.
A lot of safety is down to accountability. A distribution through an attributable marketplace or being verifiably signed.
Safety isn't a performative action, so reading a script may still confuse you or you may miss subtleties. But opting for a safer install mechanism makes a huge difference, which is we always ought to prefer apt, dnf, over the likes of curlbash, brew, npm.