Technically it would be DT2 overuling DT2, DT2 would still not have any influence over DT1 in the direct ruling sense.
What about the scenario where someone has a higher net DT1 inclusion than their net DT2 exclusions? Would we just ignore the DT2 exclusions in that case? Otherwise if we exclude them, then DT2 have overruled DT1.
but would instead help to solve the possibility of
DT1 using sockpuppets to exclude DT2 members, or the theoretical problem of DT1 including DT2 sockpuppets, that I hadn't even considered properly. Hence why the factor of 2 members required for inclusion/exclusion generally makes sense, in order to increase trust accountability.
Requiring two or more DT2 members does little to nothing to address the problem of sockpuppets. A DT1 user can make as many DT2 users as he likes. One malicious DT1 user could quite easily create/find multiple accounts to add to DT2 to achieve their desired result.
Requiring two or more DT1 members to become DT2 in the first place is a better solution, as it is far harder to game the DT1 selection process.