I really disagree with this because if I don't prioritize my offense, then I wouldn't have all that loot in the first place, my walls would be low level and I'd have much harder time to even have resources to upgrade defenses or lab. I believe it's better to make 10 million resources and 30k DE per day and lose 350k (3.5%) resources and 3k (10%) DE then to have 3 million resources and 5k DE per day and lose 50k (~1.5%) resources 0 DE. Ofcourse those are fictional numbers, but if you prioritize offense and raiding over being scared of getting raided and using shields constantly, something like that will happen.
Edit: Another important factor to take into consideration is that the loot stolen from me today and yesterday is an abnormality because usually my resources are nearly 0. I just had a 2 day period with no free builders which resulted in full storages. Ideally it's better to have 1 builder free to keep your resources close to zero by spending them on walls. I also don't use my DE atm to make full use of heroes during 1 gem boosting period, usually DE is close to zero with both heroes upgrading simultaneously.

