What Bruno proclaimed was heresy: a belief contrary to the authentic Catholic belief, yet promulgated as if it were genuinely Catholic belief, with authority of a priest.
He had multiple opportunities to recant during his trial; he maintained, however, that the core of his philosophical and theological views was Catholic.
The trial of Bruno has nothing to do with science; it was a trial of a provable heretic for heresy. That the civil authority would punish heretics at a stake is unfortunate, but the Church cannot be asked to condone fraud.
Does heresy run in families?