Many who are can't make the payment. An APR change will increase or decrease your repayment term, but will not change your minimum monthly payment. Credit card companies have made debtors prison gauche. There's more insult to injury. But you've been occasionally late credit card B. Based on that scenario, credit card A has the right to increase your interest rates.
Lenders contend that high rates are needed to off set fraud, delinquencies, and bankruptcies.
Record bank profits suggest that these justifications are hollow. Credit card companies have nothing more than a lucrative gimmick that appear legitimate because no federal laws prevent it. Congress need look no further than credit card companies for the answer. Congress must regulate credit cards. Social justice demands nothing less.