But what can we do? We can't prevent people from creating altcoins
That's exactly the point. We do not 'need' to do anything. Our preferences for a currency will do the trick. The Bitcoin network will compete with other networks. There does not have to be one (this is our current thinking within a nation state with a single currency).
Accept the fact that there will be absolute freedom.
Exactly. All we need to do is ignore the worthless alts. The claim on this thread that alts are killing bitcoin is also false, so disregard it completely.