Everyone rips off everyone else Liefied could have gotten away with it with a little more effort.
His Editors at Marvel knowingly sanctioned his activities
The motive is "time constraints" especially if you consider the first few issues of the New [at the time] X-force Title
The production Team [coz thats what it is a team] unable to move deadlines took templates of existing material then colored lettered and printed it in Quicktime.
These kinds of things happen. Its why there is a career for free - lancers in virtually every proffession.
But when you have a set budget preventing you from outsourcing combined with an immovable deadline... well either you defy gravity [break some rules] or Crash [and claim welfare]