i always instinctively believed what you said
but bodybuilding trainers and bdybuilders claim other wise
They always try to make retarded claims on how they have changed their training methods to justify how they gained 20lbs of mass in a single year because they can't be honest and say they upped the dosage, which is why you get a lot of bullshit like this going around.
If tension is the most important factor in hypertrophy then go do some shopping instead of training.
A pump is simply blood in the muscle delivering nutrients, it has fuck all to do with stimulating growth which comes in response to broken down fibres.