Some interventions are necessary, some are not. Even where India has to intervene, it has to be subtly.The primary reason for backlash is meddling in affairs of other states, it "won't" work, I repeat it "won't".
You can either try militarily or diplomatically, but it will not work out, because you are meddling in affairs of other states.
As I said before, fostering good relationship with other states is safer and fruitful on the long term. Sri Lanka is going no where, then why ruin your reputation and relation with a country?.
And as for Sri Lanka supporting Pakistan, it remained neutral, they equally helped Indians. The very concept is flawed.
In any case, Sri Lanka supporting Pakistan? I assume you talk of 1971? That's just conjecture.
In any case, talking about now, we did not interfere in Sri Lanka. The Sri Lankans themselves chose to remove Rajapaksa. We did not depose him.
The new Govt of SL is on its own willing to have more balanced relations with India and not jeopardize Indian security...which basically puts a spanner in Chinese plans.
I agree, SL is going nowhere, which is why our response to Rajapaksa's actions was very careful and calibrated. In the end we did get what we want...and the Chinese didn't.