Theoretically? Yes, as rules page has this as a its opening statement: “This website is a space for citizens and stakeholders to express their views and contribute to the EU decision-making process.”
Technically? No. You can post as a non citizen or “other” (someone from US working on the Inkscape Project used that).

What they mean by “stakeholders” and whether they’ll take these comments into account is anyone’s guess but you should be able to leave a comment.