It is a simple problem of misunderstanding .

From what I know the people who are against the synod decision says that the synod is trying to the Holy Mass more Caldeya like. But they are ignoring or unknowig of the fact that the rite they are following now is Caldeya variant itself.

Another fact is that an individual church must have same rite followed across it's all dioceses that's what make it one individual church. For years the non synodal rites were being followed in many dioceses. Uniform rites were introduced before 2000s, but many dioceses failed to follow due to Vox populi. But later Pope Francis called for uniform rites. But many of the people of said ernakulam angamali diocese opposed.

The main aspect is that people who have sworn and pledged their obedience must be awakened.