While I am not in agreement with Lou's arguments or feelings regarding the new Foreigner lineup, I don't believe that he meant that Kelly has no previous singing work in his career - rather that he (Lou) felt that Kelly had been asked to mimic Lou's vocal style and pacing when delivering the Foreigner songs during the show. (As how Lou first interpreted the song when initially recording them). I see what he means when he says this.
However, in my opinion, its a little silly of an argument. Pretty much everyone tends to copy the basic style and pacing of a song when you cover it - otherwise the song would be unrecognizable. In Kelly's case, I do feel that he puts more than enough of his own stamp on the songs as well. I see his performance as a nod and a sign of respect to Lou, appreciating the legacy.
I think that whatever differences exist between Lou and Mick (which is where I surmise the real issue lies), they are the painful ones that are causing Lou to lash out in his disagreements or anger - they are just unfortunately coming out as one off attacks towards those that really have nothing to do with the actual situation/argument. Unfortunately too, media picks and chooses what they want to present in an interview - and again, while I don't agree with Lou's assessment of Kelly, we do not know in what context the entire discussion was about, nor do we know what the entire interview was either. Stuff may have been left on the cutting room floor.
It's still my wish that the whole bad feelings thing wasn't being played out in such a public forum, but as any of us knows, sometimes when you feel wronged, you do tend to lash out and say things that are not always the best things to say.