I don't like the way they've phrased that. You can teach spaniels gundog training positively, and I've never 'punished' Jarv nor had the need to. He has had the VOD (Voice of Doom) but vary rarely and only to get him out of harms way (i.e when he was young running towards a railway line and I didn't have my whistle with me!), and I have scruffed him....to get him over fences and not as a punishment
Working cocker spaniel 'faults' when gundog training usually stem from their over-exuberance and I would never want to train that out of them - just contain it a little and direct it
Have you looked at Helen Phillips' courses on clicker gun dog training? You may feel more comfortable with her training methods
Or check out other gun dog trainers near you