Why can't you travel to proxima centauri, other than the fact that you haven't invented a convenient method of travel? If we sent you in the right direction in a Soyuz capsule, you--or at least your remains--would get there eventually, provided that you had enough energy to escape from the solar system at all.
We'd have to give you a much harder push to catch up with the distant quasars, because they are rushing away from us so fast, but in principle it's possible, let it be ever so hard in practice. No physics principle prevents you from going as close to the speed of light as you like. It may take you a gigantically large time to close the gap, and your practical window may already have closed (the universe may end in some fashion before you get there, so you should have started a very long time ago), but that's tough darts. I said "geometrically", not "practically".
(No more lawyering, now.)
If he gave up lawyering the science threads, he'd have precious little left to do in them.
That seems to be the reality of the moment. It was you that noted imprecision in the use of Universe by someone else. I merely pointed out your imprecision. The fact remains I cannot get to Proxima Centauri by any existing means. That is an irrefutable fact. Now if you wish to let someone state "If the universe is all that exists" without comment, I can allow ""Universe" as defined in BB cosmology translates to something more like "all that you can geometrically travel to"" without comment.