I wouldn't paint the whole RV with a bad brush because of a seal issue. Any machine is man made and as such not perfect. Let them replace the seal and be thankful it's not on your nickel. FWIW, that seal could have been one in a million provided by the seal supplier that was defective...it may not have had anything to do with how it was assembled.
Also seals dry out from sitting too long. It's a good idea to run the engine once a week or minimum once a month when either parked or in storage to circulate the oil and keep those seals pliable.
