Hello Yves,
I think the main issue is that early misspellings of the name Blaan created mispronunciations which were always considered to be derogatory by the Blaans. As a minority indigenous group, their voices and concerns about such things were never considered. Over the last few years, this has begun to change and the Blaan have made it clear that without recognition of their proper name and pronunciation as a start, nothing will change for them.
I am not Blaan, but I do know them and have a deep respect for their culture and history. Here are a few links, written by Blaans that can explain things much better than I can. Thank You.
https://m.facebook.com/story.php?sto...228162712&_rdr
https://www.moniquetheunique.com.au/...he-philippines
https://www.change.org/p/komisyon-sa...rophe-anywhere