The Straits Times reports that some Myanmar nationals who are working or studying in Singapore decided to attend a protest against their government.
Gatherings of 5 or more people without a permit are illegal in Singapore, so it is true that the affected nationals broke the law. However, the Singapore government's decision to not renew the visas of the affected Myanmar nationals shows that Singapore is basically on the side of Myanmar's government.
Besides, the law is crap, anyway.
The Association of Southeast Asian Nations (ASEAN) has long refused to pressure Myanmar's military dictatorship to step down. ASEAN leaders allege that their work is done behind the scenes. However, Singapore could simply have overlooked a minor infraction. Their attempt to deport these people bodes ill for hopes that ASEAN is working for change in Myanmar at all.