Oh, you're falling into the Austrian Economics trap of thinking of everything as a rational system.
People aren't rational. People who are violating the law especially aren't rational.
There is ample statistics that show increases in penalties do not have a linear impact on crime on any macro scale and in many cases, increases in punishment result in no net increase in compliance.
They do, however, from a utilitarian view, impact the overall good generated by the justice system.
Therefore increasing penalties shows a diminishing return (and a rather rapid one, in my view).
I view a 1 minute DoS attack as roughly akin to orchestrating one minute of blocking the entrance to a store (or maybe multiple stores). Such an act, while punishable by a trespassing fine, probably on the order of $100-$500, the "online" equivalent of $183,000 and two years probation does not match the act, especially when he was one of only several thousand people doing the same thing.
There are a few countries in the 1960s and 1970s that adopted the policy that there is no social justification for "making an example" of someone, and that the purpose of the justice system is rehabilitation and fair application of rules, rather than vindictive retribution, catharsis for victims, or the attempt to squash crime through draconian punishments.
Those countries (Norway, Denmark, Korea, New Zealand) stand in contrast to those countries who adopted a policy of "tough on crime" during the same period (the US, Britain, France). Looking back, the crime rates in these countries diverged, and today we find those countries with liberal justice systems having seen their crime rate drop much faster than those with draconian justice policy.
Sure, this is anecdote, but I don't buy vengance or harsh deterrence as justified reasons for rolling out the stocks on the few people who are caught at a relatively rare crime.