My understanding is that Firebase is free. However, even if it wasn't I still think the link is tenuous to the point of meaningless. Spending attention on HN does not make google any richer, it stretches the definition of the word "support" in a way that misses the point within the context of boycotting a company. If every HN reader quit the site today only a Firebase SRE would take notice, if every HN reader quit using Gmail it'd cost google a considerable amount of money.