I often go to a lot of effort finding, and using, the correct spelling of a person's name, if that person's name originates from a non-Latin alphabet (Cyrillic, Hebrew, Chinese, logographic, etc.). Sometimes I don't even bother writing the transliterated version in brackets after it, if writing space is limited (e.g. Twitter).
Writing a person's name in a local character-set is okay for phonetical ease, but it should never be confused with the persons actual real name.
Even if one dislikes a person, one should do their best to spell the name as it should be spelled, in the correct alphabet. It is not politeness, it is correctness.
There is also the heinous practice [as personally witnessed in Irish schools], where a person's name is translated between languages. Not just transliteration, but actual translations of the words used in a name.¹
You cannot translate a name. A name is syntax, not semantics. The person is the semantic.
¹ Example: "Game of Thrones" translation into Irish, changes 'Jon Snow' into a literal 'Seán an tSneachta' https://twitter.com/DirkVanBryn/status/790155947490549760
N.B. I am still undecided about the process of reversing name order during transliteration (as can happen with Asian names).
