As far as I know, DDOS attack doesnt affect customers directly, its an infrastructure debilitating technique. I just point this out ,as your post is called " [..] customers become victims"
It is nevertheless correct if you consider a customer victim of not being able to make use of a service temporarily.
A response by someone else offers a rebuttal to your thought.
Many people rely on services, which can be impacted by DDoS attacks, for an income. The example given earlier was of an online tutor losing access to the platform due to a DDoS attack and consequently losing a day's income.
...and being highly pissed-off about it. I was wishing a severe case of anal warts on the person(s) responsible.
I didn't just lose a day's income, my reputation on the site was damaged. I had to cancel one reservation, and outright missed another, which led to the site automatically restricting my ability to make reservations in the future.