Answer:
Walaikum assalam,
There is no doubt that it is an expression of piety and love for the sunna of the Beloved Messenger of Allah (peace and blessings be upon him) to follow the outward purport of his every command and example. This is the way of love, and it befits us all to strive to follow it to the best of our ability.
However, the legal limits of the Shariah are also a manifestation of the Mercy of Allah, and apply to all people in all situations, and entail no undue hardship for humanity.
The transmitted position of all four madhhabs is that it is in of itself disliked (but not sinful) for men to lengthen their trousers below their ankles, and sinful when this is done out of pride.
The established position of the Shafi`i school [as mentioned by Imam Nawawi in his Sharh Sahih Muslim, and also in his Majmu`, and confirmed by the Shuruh of al-Minhaj] is that it is somewhat disliked (makruh tanzihan) to lengthen one's trousers without pride, and sinful when with pride. The Shafi`i scholars confirm that we do not affirm that someone who simply happens to lengthen is "being proud" by "turning away" from the sunna; rather, they are doing something somewhat disliked and would only be sinful if their motivation was pride or arrogance.
The same details are found in the works of the Hanbalis, such as their great books on al-Adab al-Shar`iyya, by Ibn Miflih and Saffarini.
You can find the same in the major reference works of the Malikis.
This is also the same as what you'll find in many of the major references of Hanafi fiqh, including: Fatawa Hindiyya, Naf` al-Mufti wa'l Sa'il of Allama Abd al-Hayy Lakhnawi, Umdat al-Qari of Allama `Ayni, Ibn Abidin al-Shami's Radd al-Muhtar, Ala' al-Din Abidin's Hadiyya al-Ala'iyya, and Nahlawi's al-Durar al-Mubaha fi'l Hadhr wa'l Ibaha.
So, after all this, how can it be a subject of condemnation?
Wassalam
Faraz Rabbani.