To demonstrate that they are “intercultural:”

The former Open Air Bible Museum near Nijmegen has received 500,000 euro in subsidy from oil state Oman. With this, the museum will expand to include a House of Koran.
[…]
Oman and the museum management wish to demonstrate that The Netherlands holds “ample opportunities for intercultural cooperation”. According to a statement, they believe in “a society where cohesion and trust is stronger than mistrust and sometimes even hate”.

(via)
Islamists don’t see this as “cooperation” but capitulation. Speaking of Christians calling God, “Allah” this former Muslim makes a similar point:

The other thing this tactic misses is that Islam sees itself and desires to steadily advance its cause and rule globally. Everywhere people and countries and cultures make concessions in the name of tolerance and plurality, we do so to an illiberal expansionist ideology. It’s a tragic and dangerous mistake.

Related Post:
Dutch Bishop urges Christians to call God “Allah”