Why protecting old right is commendable (6)
I believe the answer is:
worthy
'is commendable' is the definition.
('worthy' can be similar in meaning to 'commendable')
'why protecting old right' is the wordplay.
'protecting' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'right' becomes 'rt'.
'o'+'rt'='ort'
'why' going around 'ort' is 'WORTHY'.
(Other definitions for worthy that I've seen before include "Creditable" , "big cheese?" , "Suitable; deserving effort" , "Bigwig" , "Deserving, having great merit" .)