Josiah slaughtered or sacrificed all the priests on the altars?

[TonyChanYT]

New International Version, 2 Kings 23:

20 Josiah slaughtered [H2076] all the priests of those high places on the altars and burned human bones on them. Then he went back to Jerusalem.

English Standard Version:

he sacrificed all the priests of the high places who were there, on the altars, and burned human bones on them. Then he returned to Jerusalem.

Keil and Delitzsch Biblical Commentary on the Old Testament:

slew them upon the altars on which they had offered sacrifice. ... The Israelitish priests of the high places were not Levitical priests, but chiefly from the fact that they were really idolatrous priests.

The Hebrew word H2076 appears 134 times. It means to slaughter for sacrifice. NIV interpreted as "slaughter" to avoid the theological complications. ESV translated it literally as "sacrificed" to show the irony in the original text.