Firewall Insulation after Turbocharger Replacement

[jeffL]

Just got my 2015 (Mercedes) Winnebago View 24M back from the dealer. They installed a new turbocharger due to a boost pressure regulator failure. 36,000 miles on my View.
Now, I have two questions concerning the attached photos which shows the firewall directly behind the air filter.

1. Was it really necessary to tear out the firewall insulation cover?
2. Doesn't this insulation cover (thick black fabric) have an important function? such as sound deadening and heat protection for the cab?

Am I right to feel irritated or did they just not have any choice but to leave it that way? Thanks.


JeffL
2015 Winnebago View 24M
Tucson, AZ