Why does Wikipedia list an improper pronunciation of Esperanto?

Question

The very first line of English Wikipedia's entry on Esperanto proudly informs us that the name of the language is pronounced /ˌɛspəˈræntoʊ/ (and reinforces that using two common notations and an "alternative" which does not come much closer, really). In my opinion it couldn't be wronger. This is, surely, how an English speaker would read it if they knew nothing of the language, but why would it be necessary to spell it out then? For an Esperanto speaker this would be approximated perhaps by "Es-prenĉoŭ" which feels mildly insulting, as a non-attempt at even trying*. If someone told me they spoke es-prenĉoŭ I would be tempted to doubt the fact.

The non-trivial information here that would be appropriate to list in an encyclopædic entry should be how it is actually pronounced, which is something more like /ˌɛspɛˈrɑnto/ or /ˌɛspɛˈranto/ to my best knowledge. Why list anything at all if not this? I would put it in but

1. I'm not that well-versed in IPA,
2. I think there may actually be some reason why it is like this. After all it was very likely someone who knows the language that put it there.

*) Example ("Martina Navrátilová"): This is a very good attempt. This is just English and feels super inappropriate in something that should be primarily about the tennis star.

Answer 1

The English word for the language Esperanto is ‘Esperanto’ (written the same). The pronunciation of the English word for the language is given in the English Wikipedia. Just like how the name for the country France is written the same in English and in French, but pronounced differently. The English pronunciation in no way dictates how the word be pronounced in the original language.
We do the same thing in Esperanto. We say [be̞rˈlino̞] rather than [bɛɐ̯ˈliːn] for Berlin, which in English is [bəɹˈlɪn].

If we required that every country's language, name, city names, etc. be pronounced with the native pronunciation, then pretty much no one could properly pronounce most of the countries and cities in the world. That's why we give translated names to them. English lacks one or more sounds from [e̞spe̞ˈränto̞] (or [ɛspɛˈɾɑntɔ] or similar pronunciations), hence a pronunciation is used in English with the phonemes available in English (in particular [r~ɾ] replaced with [ɹ] and the [o̞] with [oʊ̯]).

Answer 2

It is an English encyclopedia and the word is "actually pronounced" that way in English. The normal Esperanto pronunciation is given, too.

Answer 3

As others have pointed out, the given pronunciation indicates how the word is pronounced in English (more accurately, in British English).

Is it necessary? As with just about any English word, it's certainly not superfluous to indicate the pronunciation. I'd agree that there aren't too many ways to get the word "Esperanto" wrong, but it isn't necessarily obvious which syllable should be stressed, particularly for a non-native speaker of English.