Suppressing speech requires the power to make you stop. Deleting a comment on my site isn't suppressing your speech, because you can still speak where you want to except for on my site.
It suppresses speech on your site. That's what matters.
Same with government-enforced censorship: North Korea can censor speech, but only within its borders. Just because North Koreans living in the US can speak out against Kim Jong-un doesn't mean that what North Korea is doing doesn't count as censorship.
