You're vastly overstating what is "well known" about Modi, to the point of spreading blatantly false propaganda[0]. But even if you weren't, this has nothing to do with democracy or free speech. (Nor is it particularly unusual in democratic countries).
> India isn't really a full democracy; it says it is a "democracy" as long as it is convenient to say so. India has hardly ever stood for free speech or even understands what free speech is all about.
"Democracy" doesn't mean "free speech". And in fact, India's de jure protections on free speech are far greater than (for example) what the UK grants.
[0] While Modi has some figurative skeletons in his closet, it's completely wrong to say 'it is well-known that Modi has massacred colleagues based on their beliefs'.