At the surface level, it's an attack on Krebs, but there's a secondary thing going on here.
Krebs' main investigation was on Coinhive, a group which embeds Monero mining scripts in pages which run on page visitors' machines. But in his criticism of Coinhive and its association with Pr0gramm, it seems he may have cast too wide a net, doxxing and accusing Pr0gramm users who may not have anything to do with Coinhive. Instead of apologizing for this, he doubled down on it, typifying Pr0gramm users as basement dwellers who anonymously post nastygrams and threaten journalists with death.
Donating to cancer research is a direct response to that: it shows that Pr0gramm users are at least not only bad--they also do things generally considered altruistic, like donating to cancer research.
Both sides have definitely dirtied their hands: at least some Pr0gramm users are mining cryptocurrency on other people's machines through Coinhive, and Krebs has definitely made the false insinuation that Monero's anonymity is only useful for criminal activity. The open question is whether this behavior is typical of Pr0gramm or Krebs has actually accused Pr0gramm users who weren't involved in Coinhive.
I don't know who is in the right here--I simply don't have enough information to know. What information I do have comes from sources which are clearly biased. But it's interesting to see how even at this level, security cases are being tried in the court of public opinion.