There are two approaches to drafting legal agreements. One way is for the law firms to make these documents extremely prescriptive resulting in 100s of pages of legal language. A second and more streamlined approach is to cover basic concepts while making everything else implied. Good examples of this second approach are the SAFE and the Cornerstone LPA. It's just not necessary to go into this level of detail for funds that are less then $50m because any type of lawsuits would be fatal to the fund and the LPs as a result. Bigger funds will have a Private Placement Memorandum to specify all the things that can go wrong, and since there is so much more capital on the line, the additional fund expenses are worth it.

Now, to answer you question more directly - since the fund manager is a fiduciary and is also indemnified from damages except for Malfeasance, this type of clause is not necessary.