Well, some suffragists were arrested just for protesting, power being quite fond of abusing its authority when given the chance. But yes, the riots and bombing and arson campaigns are very under-emphasized in popular perception of the Women’s Suffrage movement.

Si vis pacem, para bellum. Negotiation happens from a position of strength, not meekness, even if your end goal is to resolve it without needing to execute everyone who opposed you. A show of force gives your words weight when you say “We won’t take it anymore!”