Nusach Sefard doesn’t tolerate people who do this. People who do so are not worthy
to daven Nusach Sefard. ??????
Shu”t Chasam Sofer (O.Ch. 15b-16 ) The Shoel asks the Chasam Sofer , People
who wear woolen clothing, if they are allowed to serve as a Shliach Tzibur. The reason for not
allowing, is because Nusach Sefard doesn’t tolerate people who wear woolen clothing. People
who do so are not worthy to daven Nusach Sefard.
In Teshuvah # 15 the Ch. S. seems to ridicule this statement. He claims, even if the chumra comes
from not wanting to be nichshal in Shatnez, it doesn’t make sense to differentiate between
Nusach Ashkenaz and Sefard.
In Teshuva 16 , Although The Ch. S. still disagrees with the Shoel , he takes him more seriously,
being the Yismach Moishe confirmed , the disallowing of a Shlaich Tzibbur who wears wool
( to daven Nusach Sefard).
Most Chasidic Rebbes and some Chasidim wear silk Bekeshes for this reason .
It is possible, this Minhag originated by a *Gadol who made a statement, " people
who daven Nusach Sefard don’t wear wool clothing". He was referring to Sefardim who reside
in warm countries. All he was trying to say, was a fact, sefardim in warm climate
countries don’t wear wool. (they have an advantage not to be nichshal in Shatnez). He never
meant to say , davenening Nusach Sefard requires one not to wear wool clothing.
* my eigene fantazyes