Yes, we do agree on that.
The assailants were minors and thus mostly got probation sentences. That's due to German law. This was criticized widely.
Are you allowed to find out the mobile number of the perpetrators and harass them on WhatsApp? Well, not under German law. Two wrongs don't make a right and so on. It's true that she did not get the leniency the assailants got, because she is not a minor (and had been caught stealing before). She was sentenced to a weekend in jail. That is 3 days.
Are both cases comparable and allow us to draw larger conclusions from the differences in their sentencing? I don't think so. They are completely different and only linked by the victim of the latter being a perpetrator of the first.
It does make for a sensational headline, though!