Abel (Niels Henrik) had a degree in theology, so it is likely in his original writing he rather used the Norwegian equivalent of work of the devil or devil’s work.

This is plausible especially when we know that the sentence you quoted was a part of a letter Abel wrote on January 16 1826 to Holmboe, an other Norwegian mathematician. This means the letter was likely to be written in Norwegian, not in French.

Taking these historical and social environments in which the letter was written, may be the question could be shifted to: is the French translation fatal correct? But the best to do is to check how the letter was written originally in Norwegian of that time (if you speak Norwegian)

Note that even in English, work of the devil is not the only expression used to translate the original letter of Abel (I, for instance, found terrible).

I hope this helps a little.