2. You balance it by allowing free speech and encouraging robust debate rather than demanding loyalty tests or speech codes. Restricting speech or telling people that they "can't say that" is an excellent way to result in groupthink; encouraging free speech and especially a culture of free speech that respects differences is the best way to prevent one-sided groupthink. Such one-sidedness has many negative consequences, including (but not limited to) ineffective actions, alienating wider groups of people, supporting bad science, and limiting the scope of discovery and study.