It is definitely not good to remove all foliage from junipers but that does not mean they store energy in foliage. All trees store resources in all parts of the plant - roots, trunk, branches and foliage. It is meaningless and quite untrue to say certain plants store energy in different parts. Those same olders and wisers will also say that pines store energy in the roots but we still cannot chop a pine to bare wood.
Healthy trees will certainly bud much better than weak ones but that is also nothing to do with where energy may or may not be stored. Every species will respond to any pruning better when it is fit and healthy.
I trimmed and wired several shimpaku yesterday even though they are in full growth mode. Experience shows they will have no problem as a result. I prune junipers whenever I have a tree that needs it and the time to do it and certainly don't have a yard full of dead trees as a result.
having said that there are a few caveats with junipers in particular:
- Roots recover slowly so best not to do much pruning for at least a few months after root pruning and even longer after severe root pruning.
- Severe bending during the growing period spring - mid summer often results in dead branches so best to defer shaping until less vigorous growth. Usually after mid summer is OK.
- Pruning when there's lots of juvenile foliage will likely trigger more juvenile foliage. The pic shows lots of spiky needle type juvenile foliage so I'd agree with Treeman that it would be best to stay away from this one for a year or so until growth settles down to adult scale foliage.