Is it rude to read Sukhmani Sahib path when kirtan is on at the gurudwara? Because i see people doing this and just wondered if it was disrespectful.

Gurbani is Guru which gives spiritual knowledge and wisdom how to adopt and assimilate Virtues of the God in the mind (Mann). That’s only possible if it is read slowly with understanding and assimilating the essence, as churning the curdled milk slowly and steadily with a churning stick. Reading path without understanding is meaningless as Guru Nanak says
ਪੜਿ ਪੜਿ ਗਡੀ ਲਦੀਅਹਿ ਪੜਿ ਪੜਿ ਭਰੀਅਹਿ ਸਾਥ ॥ ਪੜਿ ਪੜਿ ਬੇੜੀ ਪਾਈਐ ਪੜਿ ਪੜਿ ਗਡੀਅਹਿ ਖਾਤ ॥ AGGS 467
Parr Parr Gaddi Ladheah Parr Parr Bhareah Sath || Parr Parr Berri Paeai Parr Parr Gadeah Khat ||
ਪੜੀਅਹਿ ਜੇਤੇ ਬਰਸ ਬਰਸ ਪੜੀਅਹਿ ਜੇਤੇ ਮਾਸ ॥ ਪੜੀਐ ਜੇਤੀ ਆਰਜਾ ਪੜੀਅਹਿ ਜੇਤੇ ਸਾਸ ॥ ਨਾਨਕ ਲੇਖੈ ਇਕ ਗਲ ਹੋਰੁ ਹਉਮੈ ਝਖਣਾ ਝਾਖ ॥੧॥
Parreah Jete Baras Baras Parreah Jete Mas || Parrea Jeti Aarja Parreah Jete Sas || Nanak Lekhai Ek Gal Hor Houmai Jhakhna Jhakh ||1||
We may read and read loads of books; we may read and study vast multitudes of books. We may read and read boat-loads of books; we may read and read and fill pits with them. We may read them year after year; we may read them many months there are. We may read them all our life; we may read them with every breath. Nanak says, only one thing is of any account, which is, getting knowledge and wisdom from them; everything else is useless babbling and idle talk in ego. That means reading Guru Granth Sahib or doing Path without understanding and getting knowledge is meaningless.