Probably because it had no bearing on this case.
I am not familiar with the ruling and it would be interesting to read the decision.
Since Cleaver was no eligible, but allowed to stay on the ballot, one could easily think that the decision to remove is not up to the individual states, but to Congress. If that was the decision, then there is definite relevance to the Trump v Colorado case.
It bears in this regard: They said that even if a candidate is ineligible to hold office, people have a right to vote for him or not. But the states don’t get to add qualifications. Like in the case where they said states cannot term limit Federal officeholders, or bar them from the ballot.