WS Saeen, kush ahiyo tawahan? Legal systems have got nothing to do with what you're trying to say. As an agent Dr. Faisal made it crystal clear in his opening statement as to why Pakistan opted to appear which you seem to have missed. In case if you don't know ICJ compulsory jurisdiction is subject to the reservations of the state, if ICJ violates reservation "Exclusion of ICJ jurisdiction from the matters related to national security" Pakistan will have every right to walk out without out any legal repercussions. What we saw the other day was preliminary hearing, in other words the court still has to decide admissibility of the Indian application.
Ill make it simple for you, look Saeen every state follows its own domestic laws, ICJ under laws can't supersede domestic laws of any nation. Article/Section 164 CPC governs confessional statement both in India as well as in Pakistan, please read it online.
In nutshell -- What you're saying is a good solace but not practical at all. BTW have you read what kind of jurisdiction does the court, ICJ, have in actuality?
Chai zara dhayan se pijyay ga, garam chai mooh bhi jala deti hy. Good day!