The LP-shape Warmoth offers now is more of a modified LP than a measurement-for-measurement duplicate (modulo the necessary changes to accommodate a bolt-on neck, rather than a mortise and tenon joint).
Dean may have a deal with Gibson, or may have adopted a "we've been doing this so long there's no way Gibson can win since we've already diluted whatever trademark they claim in this body shape" position. Dean is likely richer than Warmoth, and can better afford to withstand a lawsuit. Warmoth's business decision was to get out of the Gibby trade - not much more to it than that. Anything they offer now is sufficiently different from the Gibson parts that they are unlikely to get sued - and it may well be that they had their new designs vetted by Gibson to ensure they would not be considered infringing. That part, of course, is just my speculation, but one way to avoid getting sued is to get the potential plaintiff to ratify your actions.