I'll edit to be more precise: A CDT agent thinks "me and an LDT agent facing off against 99 other LDT agents in a oneshot PD tournament" is a fair test of it versus the LDT agent. A CDT agent does not think that "Me facing off against 99 CDT agents and 1 LDT agent, versus an LDT agent facing 99 LDT agents and 1 CDT agent" is a fair and symmetrical test. On the CDT view, the LDT agent is being presented with an entirely different payoff matrix for its options in the second test.