"Anti-housing NIMBY are afraid to see their overvalued houses reduce in price, while anti-datacenter folks see how loud and damaging they can be and say no"

This is an oversimplification. Many people who are NIMBY on housing are that way because they don't want higher density, low income housing, more traffic, more noise, etc. The reasons for NIMBY doesn't really matter as it's still the same concept and outcome - opposition to building in a specific area. The only thing that changes is one's subjective opinion on which is justified or not.