The breakers were originally implemented as a response to Black Monday in 87, which was before algorithms were so dominant, but it happens that humans are really good at panicking and acting irrationally too.
87 had a significant algorithmic element to it too though according to many accounts via "Portfolio insurance" products which were algorithmically traded, as well as traders arbitraging between the index futures markets and the cash market.
From the 1988 "Report of the Presidential Task Force on Market Mechanisms : submitted to The President of the United States, The Secretary of the Treasury, and The Chairman of the Federal Reserve Board":
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Our understanding of these events leads directly to our recommendations. To help prevent a repetition of the events of mid-October and to provide an effective and coordinated response in the face of market disorder, we recommend that:
• One agency should coordinate the few, but critical, regulatory issues which have an impact across the related market segments and throughout the financial system.
• Clearing systems should be unified to reduce financial risk.
• Margins should be made consistent to control speculation and financial leverage.
• Circuit breaker mechanisms (such as price limits and coordinated trading halts) should be formulated and implemented to protect the market system.
• Information systems should be established to monitor transactions and conditions in related markets.
