the marchers did achieve their purpose. Across the world, people noticed them, exercising their Constitutional rights. Although there can be negative effects from protests, in the end no important percentage is hurt. Yes, some people are arrested. Yes, tear gas is used in some cases. And yes, some protesters get out of hand and damage property. But that is to be expected any time millions of people are in one place at one time. A more serious reason against resistance to laws is that, if you are not violent, you will not get the antagonist's attention and thus change nothing. I disagree. Throughout history we have seen the effects of protesting laws peacefully. The most recent victory peaceful protesters have seen was the (temporary?) halt of Donald Trump's travel ban. The ban halted immigration from several Muslim-majority countries (with no Trump businesses) in the Middle East. The very same day Donald Trump signed the executive order issuing this ban, protests broke out at airports across the country. Although the protesters in this case were not protesting a law per se, they were peacefully resisting with great success. To directly answer the question, peaceful resistance to laws will always positively impact a society, so long as it remains peaceful.
Though there may be casualties along the way (such as a great deal on parking in downtown Chicago), ultimately people in America have been guaranteed the right to peacefully assemble to protest that with which they disagree. If the founding fathers had not believed that the ability to peacefully resist is vital to the functioning of a society, they would not have included it in the very first change to the Constitution. If somewhere along the line the judges of the Supreme Court had decided that no, we no longer need this right, or that this right is hurting society, they would have changed the Constitution to reflect that. No, we as Americans are guaranteed these basic rights for a reason. We are living in a free society, and a free society's best tool for expressing its opinion of laws is to peacefully resist
them.