Hindus Empires conquered vast territories and held them for many centuries, they didn't do this by promoting peace and mutual understanding. Empires aren't created for the benefit of the conquered after all.
Just like any other imperial conquerors, they killed or enslaved many civilians, it was the nature of ancient warfare. It was pretty much a necessity, for a variety of reasons (to reduce chance of revolt, to pay soldiers, to act as a warning so others would submit quickly, etc.
They also destroyed and looted some of the temples, just as the Muslims did. There was lots of wealth to be extracted after all, and the soldiers needed paying.
Also if you need to feed tens of thousands of soldiers, you generally do that by stealing it from the people you are conquering (or even those who are nominally on your own side).
So the idea that Hindus "nobly" conquered much of South/South East Asia without inconveniencing the masses is just a feel good myth.
All cultures, including Hindus, have been violent and committed atrocities: raped, thieved, looted, killed and destroyed. Those that have been victims could easily have been oppressors had a few battles turned out differently.
Kindly note that even before the Chola King, Rajendra, went with his navy against the SriVijaya empire, Indian influence was already there because of Buddhism.
"In 1025, Rajendra Chola also successfully invaded the cities of
Srivijaya empire, another thalassocratic empire based on the island of Sumatra. However, this invasion failed to install direct administration over Srivijaya, as the invasion was short and only meant to plunder the wealth of Srivijaya. However, the Chola influence on Srivijava would last until 1070 (i.e., less than 50 years), when the Cholas began to lose almost all of their overseas territories."
Chola dynasty - Wikipedia
The South-East Asian kingdoms were of mixed people or of indigenous influenced by Hindu culture. I do not think there is a history of Hindu atrocities on indigenous people.
If you or any member of the forum knows about such atrocities, they are welcome to post it here. I say this because indulging in atrocities is not a part of Hindu culture. Of course, the kings and their armies may have had wars, but that will not affect civilians. That is the tradition.
For example, I could not find the word killed or killings in these Wikipedia pages:
Hinduism in South Asia - Wikipedia,
Greater India - Wikipedia,
Southeast Asia - Wikipedia,
Srivijaya - Wikipedia
"
Ambitious local leaders realized the benefits of Hinduism and Indian methods of administration, culture, literature, etc. Rule in accord with universal moral principles, represented in the concept of the
Devaraja, was more appealing than the Chinese concept of intermediaries.
Another theory states that Indianization spread through the warrior class of
Kshatriya. This hypothesis effectively explains state formation in Southeast Asia, as these warriors came with the intention of conquering the local peoples and establishing their own political power in the region. However, this theory hasn't attracted much interest from historians as there is very little literary evidence to support it.
The most widely accepted theory for the spread of Indianization into Southeast Asia is
through the class of Brahmin scholars. These Brahmans brought with them many of the Hindu religious and philosophical traditions and spread them to the elite classes of Southeast Asian polities. Once these traditions were adopted into the elite classes, it disseminated throughout all the lower classes, thus explaining the Indianization present in all classes of Southeast Asian society. Brahmans were also experts in art and architecture, and political affairs, thus explaining the adoption of many Indian style law codes and architecture into Southeast Asian society."
Greater India - Wikipedia