Why are you surprised? Sikhs have history of blaspheming on Hinduism 1) Bhai Bharu broke nose of naina devi silenced the brahmins who came to complain to Hargobind Singh . Bhai Bharu mocked the Brahmins & the goddess
Kharak singh son of ranjit singh broke a Shivling on night of Shiv Ratri
Sikhs in 1905 threw away vishnu idol from Hari Mandir.
Sikhs killed 5000 vairagis and nagas in kumbh Mela