Freedom of speech is only applicable against the government, and even then it’s a right that can, and in some cases should, be restricted.
Twitter, as pointed out previously, is a private company and not a government, and can set their own rules as to what is acceptable on their platform, as long as that falls within the law (ie they can’t tolerate hate speech which would otherwise be banned).
Katie H is still free to spew whatever vile claptrap she chooses, she just doesn’t get to do it on twitter anymore (and in fact has shifted to another platform).
Now if you don’t like that twitter has banned x and not y, again, they are a company not a government, so take it up with Twitter.