As sex education site O.school found, Apple’s new web filter is pretty bad. But all web filters are bad. Even Microsoft’s web filter, for Windows 10 and Xbox One, allows neo-Nazi websites and instructions for committing suicide.

Windows 10’s web filter is available when you add a child account to your PC. You can then visit the Microsoft Family website, click “Content Restrictions” for that child account, and activate the “Block Inappropriate Websites” option.

This setting only affects the Microsoft Edge and Internet Explorer browsers, but the filter automatically blocks other common browsers like Google Chrome and Mozilla Firefox from running while it’s enabled.

We ran some quick tests and found that, while Microsoft’s web filter doesn’t approach the level of awfulness in Apple’s new web filter, it’s also nowhere near perfect.

Despite the description saying this will “block inappropriate websites” and prevent “results that are too mature” from appearing, it seems like this filter mostly blocks pornography.

That’s fine, but you can still access some nasty stuff. Microsoft’s web filter won’t let a child visit 4chan, but it does allow neo-Nazi news website The Daily Stormer. It doesn’t block searches like “how to join isis” or “how to commit suicide” either.

In fact, Bing’s results for “How to commit suicide” are a little too helpful, showing an instructional website that lays out how to kill yourself up top, while Google shows a suicide prevention phone number and a suicide prevention website up top. Microsoft’s web filter lets a child read all about how to kill himself or herself.

Bing should suggest helpful things like suicide prevention phone numbers instead of the horrible things it’s been suggesting.

(And please, if you or someone you know is considering suicide, seek help.)

We could probably find many more bad things that Microsoft’s web filter is letting through. That’s because this is a problem with all parental control systems that filter a list of websites. The list is always incomplete and won’t block some nasty websites. Or, in some cases, the list blocks helpful websites.

This isn’t just a Microsoft problem. Whatever parental controls you’re using, you can’t rely on them completely.

If you want to block websites for young children, we recommend relying on a whitelist. In other words, only allow access to a certain small list of preapproved, good websites. A blacklist is an attempt to make a list of bad websites on the web, and it will never work perfectly.

Thanks to The Verge for bringing the problems in Apple’s Screen Time parental controls to our attention. We first learned about Bing’s suicide prevention problem via @zaphrode on Twitter, too.

Image Credit: Microsoft, South Park Studios