It's only logically moot specifically because there's only two options. Refusal to participate doesn't change the fact that it will either be Biden or it will be Trump in the Oval Office next year. Choosing a third party will also not change that fact.

This is simplistic. There are only two outcomes to the upcoming election, but there are countless political strategies, many of which do not treat 2024's presidential election as a totalizing issue. Other people, for example, think that what matters is building a strong leftist opposition so that we can escape the cycle of Republican vs Republican-lite elections, accepting that it means not giving unconditional support to so-called "moderates" for whom genocide is moot. Your logic only makes sense because you are question-begging by framing the question like the future doesn't exist beyond the next four years.