His proposal is obviously motivated by the Croatian right-wing politics.
I'm not suggesting anyone's politically-motivated arguments are better than anyone else's.
Why would my hypotheses be politically motivated? I just don't get what you are trying to say. I am not a fan of the Croatian right-wing politics, I am a libertarian. And, even so, somebody motivated by the Croatian right-wing politics would probably claim (without evidence) that the toponyms come from Croatian, not that they don't come from Croatian. Daniel, do you get what that guy is talking about?
The name of the river Vuka, for instance, obviously comes from the common Serbian personal name Vuk.
Then, how it is that the name Vuka is attested back in antiquity, way before there were Serbs (or even Slavs) there, as Ulca? Also, how is "Vuk" an exclusively Serbian name? It's a word for "wolf" in both Croatian and Serbian.
Also, a bit of an off-topic remark, but if the Serbs there would be so much better off had Serbia conquered Vuka, why don't they move to Serbia then? You know, to a place where everyone shares their language and presumably also their religion? Could it be that they feel they are less oppressed by the Croatian government (which, I agree, doesn't treat people of different nationalities fairly) than they would be by the government of the Serbian president Aleksandar Vucic?
the name "Serbinon" is attested on the Ptolemy's map,
Historians don't quite agree where Serbinon was, but the map you've linked to doesn't quite suggest it was near modern-day Zagreb. Nor does, as far as I am aware of, any Croatian historian agree that Serbinon was there.
Zagreb is on the Sava river, Serbinon (at least on the map you've shown here) is on the northern bank of the Drava river (that is, somewhere in south-west Hungary). Zagreb would be somewhere near Siscia and Segestica and north-west of them, not north-east (unless you assume all the traditional ubications are somehow wrong).
Besides, the right inference from the data you've shown is that Serbinon was named after the Serapia river (for it was near its confluence, at least on the map you've linked to), not after the Serbs (who, according to the mainstream history, never were there to begin with, and were not even close to there until at least the 5th century CE).
I find it very hard to believe languages actually behave that way.
How is anything else even conceivable? Sound changes that would, for example, randomly (without a phonological rule) change some 'd'-es to 't'-es, some 'd'-es to 'z'-es and left some 'd'-es unchanged would make a language incomprehensible rather quickly. Or do you think that many words in languages come into being without etymologies, that many words are formed just by picking random sounds? That would also make a language incomprehensible.
I am pretty sure that if you tested those rules with more such words, they will fail to correctly predict how the shapes of the words changed more often than not.
So, you are not comfortable with hypotheses that can be hypothetically falsified? Sorry, that's what science is all about.
And I am also pretty sure no linguist specializing in Serbo-Croatian would affirm you the rules in the table are correct.
Have you tried asking some? Chances are, he or she knows about it less than I do and will be impressed by my work.
So, which approach do you think is more scientific?
Isn't it obvious by now? I'm basing my explanation that "Zagreb" comes from Illyrian *Dzigurevos on a set of potentially falsifiable hypotheses, presented in that table on my web-page. You are running away from making falsifiable hypotheses about sound changes because "I don't think that's how languages work.".