Such actions can be done in following ways:
One doesn't intend to harm, but due to some indirect actions, a person ends up damaging something. This doesn't result in anything as there was no purpose behind it. Some people feel sorry and some don't. Both are OK.
The Qn is not about this category, so not discussing much.
Many have the only ability to hate, they simply can't love. Hence they use this "hate" as a tool to worship God. If they are serious about what they are doing with single pointed steadfastness, then it's a kind of devotion (Bhakti). Which is called Shatru Bhakti. i.e. Worshipping god by animosity
Ultimately this hateful person either wants to kill the god or wants get killed by that god. Examples:
And while Sisupala was speaking thus, the exalted slayer of Madhu thought in his mind of the discus that humbleth the pride of the Asuras. ... the chief of the Yadus, that slayer of all foes, in anger, instantly cut off the head of the ruler of Chedi by means of his discus. And the mighty-armed one fell down like a cliff struck with thunder. And, O monarch, the assembled kings then beheld a fierce energy, like unto the sun in the sky, issue out of the body of the king of Chedi, and O king, that energy then adored Krishna, possessed of eyes like lotus leaves and worshipped by all the worlds, and entered his body. And all the kings beholding the energy which entered that mighty-armed chief of men regarded it as wonderful. [source]
- RAvana -- see this answer, how Rama turned Ravana into nothingness
Whichever god we love or hate, we end up merging with them. Depending on emotion, the merger would be either pleasant or despicable.
Now some people simply deride the god to have some distorted fun.
Yes, this is also a worshipping like above, but it's not steadfast or serious. Such people get their dues exactly in the same way due to Karma.
BG 4.11 - The way they approach Me, exactly in same way I serve them; O Partha, all human beings follow My path in every way.
BG 9.11 - Ignorant people who have taken a human body, make fun of Me, not knowing My supreme nature as the Lord of all beings