Because the Left-Centerleft coalition only won a plurality, not an outright majority. More people voted for Macron's center right party or one of the right wing coalitions.

These people march in the streets and throw molotovs at cops because of a proposed 3 year increase in retirement age, but the sitting government entirely ignores their votes and nothing happens?

I admire that they value three years of their life mkre than the civic religion.

The new prime minister has also spoken in favor of raising the retirement age, so it's even more confusing