I agree with you.
Relating the original Boulder error (is "is an ICANN TLD" misleading or even incorrect?) and how the PSL is built,
The Public Suffix List is subdivided, using markers in the comments, into two sections, labelled as ICANN domains and PRIVATE domains.
ICANN domains are those delegated by ICANN or part of the IANA root zone database.
I think I have gotten lost somewhere, because nic.in (well, all the in SLDs) is listed in the ICANN section.
What does "delegated by ICANN" mean here? Because nic.in is surely not directly delegated in the IANA root zone database. 
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Does nic.in appear in the ICANN section just because in does?
Also,
Apparently DMARC uses it!