I disagree. There is no reason why Reddit would want to allow hateful content on their site. I think that banning hateful subreddits improves free speech in some ways by protecting marginalised groups and making them feel more comfortable expressing their opinions. For example, if you have a site which is predominantly used by one group, and this site has no restrictions on hateful speech, members of that one group could freely discriminate against other groups. The other groups wouldn't want to use that site anymore if they are being discriminated against. By banning hateful speech the other groups can now use the site and express their opinions. In order to allow people to speak freely, we have to put limitations on certain types of speech.