These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fanon Discontinuity: This is how most Foolkiller fans treat any post 1991 appearances of Salinger of Gerhardt, in which they clearly act out of character:
The bizarre Lunatik episode in which a renegade FBI agent allegedly had Salinger temporarily released so that he could frame Ghost Rider expy Vengeance. The Foolkiller's method of executing his victims by burning is similar to Vengeance's. That's all that the two have in common however, except for the fact that Vengeance does not kill, he only torments.
Gerhardt was amongst the many villains who escaped from The Raft and joined The Hood's army during Civil War. Still later, he was seen in a mental hospital picking fights with Deadpool and losing.
Harsher in Hindsight: The 1990-91 Foolkiller limited series was wrapping up around the same time that Jeffrey Dahmer and his crimes were revealed. Comics have to be written and illustrated months ahead of their publishing date so this had to be just coincidental. However, the ninth issue was released in July, the same month that Dahmer was apprehended. Although readers knew all along, it was in this issue that police discovered the identity of the Foolkiller.