They're speaking English. The correct pronunciation of a "V" is in fact to make the english "V" sound.

Nope. Proper nouns are to be pronounced in whatever way is dictated by the country of origin.

Also, no, English is not very reliable when it comes to spelling vs. pronunciation.

(Former diction teacher, here.)

I'm going to avoid being snarky and point out this is merely the way you taught it. There is not hard and fast rule that says you have to do it this way.

Also, Vs are actually pretty consistent in English. Can't even think of a word with a V where the V doesn't sound like a V.

What's interesting here is that the exception proves the rule.

V is actually the only letter in English that is never silent.

Most other letters also have various possible renderings into pronunciation, especially the vowels—"i" for instance can end up being at least 5 different vowel sounds and also some consonant sounds.

So yes. As I pointed out, English is extremely irregular orthographically, in stark contrast to languages like German, French, or Italian, all of which have extremely reliable and simple pronunciation rules.

The pronunciation is already normalized in English, and most people already pronounce it correctly in English for other English speakers.

Expecting non-German people to speak with German pronunciation is plain arrogant.