Must be a very small group. Vast majority of indons, including those who look like muud, do not consider themselves as 'malay'.
The javanese are wary, very wary of malay nationalism.
If you go Sumatra, those in riau, palembang, medan, batam, bintan, aceh all consider themselves as malays.
same in kalimantan around pontianak, banjarmasin, pakangkaraya, samarinda, balik papan....all malays.
They all exchange malay culture on you tube giving videos of their kampung or cities. Asperisiasi dari kepri i think.
Malay sultanate in sumatra were all butchered by javanese migrant workers in 1937 i think for being too friendly to the dutch and chinese and having a privileged lifestyle.
The
East Sumatra revolution, also known as the
East Sumatra Social Revolution, began on 3 March 1946. Across 25 "native states", many sultanates were overthrown and mass killing of members of the aristocratic families were performed by armed
pergerakan groups (Indonesian nationalists).
[1] To the opportunistic
pergerakan militants (especially
Communist Party of Indonesia leaders
Abdoe'lxarim M. S. and Luat Siregar), the revolutionary movement was seen as one of the means for East Sumatra to be freed from colonial overlordship and to join the larger
Indonesian National Revolution.
[2] Participants of the revolution were believed to be provoked by leaders to kill aristocrats and create violence. These belligerents had three prime objectives: to eliminate the sultans and aristocrats (who were seen as Dutch allies), to seize their wealth (as sources of funding for the Indonesian independence campaign) and to eliminate the region's feudal social structure.
[3] The revolution brought about the formation of the
State of East Sumatra, which was dissolved when the region became part of the Indonesian republic