The Constitution makers were not faultless messiahs, they too were fallible mortals and so we shouldn’t hesitate while amending key provisions of the Constitution in the interest of the society even if it changes its basic structure (too some extent).
The fact that the Constitution makers bestowed legislators with the liberty of amending the Constitution was in fact an admission of their limited knowledge and the perceived inability of the Constitution to deal with changing circumstances. I refrain from using the term ‘Constitutionalist’ because no Constitution is immaculate and devoid of grey areas or loopholes and so the question of standing by the Constitution under all circumstances doesn’t arise. We shouldn’t shy away from pointing out the limitations of our Constitution and asking for rectifications or additions in it. Remember that everything which Hitler did during the Nazi Regime in the Third Reich was legal as per the erstwhile law prevalent at that time.
There’s always a need to keep amending the Constitution for the sake of contemporary compatibility but unfortunately the Indian Constitution has become virtually non amendable since the late 80’s because to amend the Constitution, two-thirds majority is required in both the Houses of the Parliament and such a bill needs to be ratified by half of the State Legislatures if it relates to the principle of federalism. No ruling government commands such absolute majority or staggering support and so an amendment to the Constitution can be made only when there is a wide national consensus.