Your speech is effectively censored by the moderators because you cannot use that tool as intended, to reach audiences with the same ease other types of speech can.
It's like requiring a newspaper to "moderate" all articles by a certain author publishing them in the form of a short notice "If you are interested in the writings of Mr. Smith, who may or may have not published an article for today's issue, then please send a self-addressed enevelope to PO-Box ....".
But you can still stand outside your home and say whatever you want. You can print up and distribute flyers. You can set up your own web site too.
While I despise the business models and actions of pretty much all the "social" media actors, they are not required to provide you with a platform.
You can still say whatever it is you want to say, but those private actors have no responsibility to act as a megaphone for you.
This dichotomy (free speech for all, but no one is required to offer a platform) works in liberal societies because you have a diversity of publishers.
You can't come to my house, sit on my couch, eat my food and watch my television unless I say you can. If you try to do so without my permission, I'm within my rights to throw you out and, if you resist, use force to remove you.
How is usage of a private company's private server resources any different?
If you push that argument to the extreme, why should anyone be allowed to publish anything in our county? They can always go someplace else and speak their mind, but we don't want it around here.
What I'm saying is that exists a gradient of power between the dictatorial (state censorship) and inconsequential (your couch), and we have a social contract that allows the same suppression of speech in the latter but disallows it in the former. We call the consequential type "censorship" but it's the same basic action, there is a gray area where private agents working under the authority of the state can be just as powerful censors as the state itself.
For example, if private banks deny services to a newspaper hostile to the government, I could take your argument and spin it around, they are "free" to publish on their own pocket cash, private banks are not forced to "offer a platform". But we clearly understand that publication will lose advertisers, fail commercial and the interests behind the banking ban will have succeeded in suppressing free speech - suggesting them to distribute leaflets will not help.
The cut-off point where private suppression becomes consequential censorship is, in my opinion, when the gatekeepers of speech are centralized and oligopolistic, like for example social media and, unlike for example, traditional print media. A single publication denying publication is perfectly fine, as long as others exists and have reasonable similar access to distributions channels. With the death of traditional print media and the highly concentrated nature of the visual media and internet space, this less the case.
You can of course publish on your blog with zero traffic, but you are effectively shut out of the relevant distribution channels, you are effectively distributing leaflets in your corner of the street.