Besides removing supposed temptations to idolatry, Islamic jihadists want to destroy the artifacts of non-Muslim civilizations, because doing so testifies to the truth of Islam, as the Qur’an suggests that the destroyed remnants of non-Muslim civilizations are a sign of Allah’s punishment of those who rejected his truth:

Many were the Ways of Life that have passed away before you: travel through the earth, and see what was the end of those who rejected Truth. (Qur’an 3:137)

This is one of the foundations of the Islamic idea that pre-Islamic civilizations, and non-Islamic civilizations, are all jahiliyya — the society of unbelievers, which is worthless and must be shown to be inferior to Islam. Ruined houses of worship serve that purpose.

“4 minor boys arrested for vandalising Hindu temple in Thar village,” by Hanif Samoon, Dawn, January 27, 2020 (thanks to The Religion of Peace):