Sumitraa had twins - Lakshman and Shatrughn then why Raam should say that?

Its answer has already been provided by Tulasee Daas Jee himself there only. Immediately after the couplet quoted above, we find the following couplets - Meaning: "Umaa, (continues Lord Shiv), the Lord of the Raghu is one (without a second) and indivisible; He exhibited the ways of human being only because He is so compassionate to His devotees! The host of monkeys that surrounded the Lord were distressed to hear the Lord's frantic wailings. Presently arrived Hanumaan like a heroic strain in the midst of pathos!"

So Shiv Jee and Tulasee Daas Jee have themselves termed these wailings of the Lord as frantic. Which means that the emotions of the Lord at that fateful moment amidst the gruesome battleground of Lankaa, when such a beloved brother as Lakshman is lying unconscious in the jaws of death, the same Lakshman who is Raam's very life-breath moving outside, should not be measured on the scale of truthfulness and propriety etc.

No one else in this world is dearer to Raam than Lakshman, not even Seetaa, this is very much evident from the uttering of the Lord here. Also in Vaalmeeki Raamaayan, even Seetaa was aware of this fact, which She also told to Hanumaan - "Lakshman, the beloved brother of Raam is ever dearer to that prince (Raam) than I (Seetaa)"

If you say that Lord has mentioned Aanjaneya as "You are twice as dear to me as is Lakshman", then it is to be taken in the same sense as when someone says "You are dearer to me than my life" ...thus Hanumaan is twice dearer to Raam, but we must not forget that Lakshman is still the very life-breath of Raam. This also shows the level of oneness with Lakshman that Raam has; He could frankly say this to Hanumaan in front of Lakshman himself, without least bothering about him, this proves indeed that Lakshman is Raam's alter-ego. Life-breath stays with us silently; even if we consider someone greater than it then also it doesn't leave of us.

Although we, with our tiny intellect can never compare the two Param Bhakt of Raam, Bharat and Lakshman, but still this is a fact that ..Raam could bear and survive many days in separation from His beloved Jaanakee; and He could even survive the separation from His dearest brother Bharat for 14 years; but anytime when the question of separation from His life-breath Lakshman arose, He could not just imagine His existence without him even for a day. He is ready to give His life when He beholds Lakshman lying unconscious and also later on in Vaalmeeki Raamaayan, Uttar Kaand also when He had to exile Lakshman, He at once decides to leave this Prithvi for His divine abode.

So if such a Lakshman is lying unconscious in front of Him, then can we expect Him to speak a well measured out speech? This words spoken in lamentation are an attestation to His most piteous state at that moment....  it just shows the sorrowful state of His mind!

In Vaalmeeki Raamaayan also Lord's pathos is such that He mentions - Meaning: Wives may be found everywhere and kinsmen too can be had everywhere, I, however, see no place where a uterine (real) brother could be had.
[Vaalmeeki Raamaayan 6:101-15]

Here Lord addresses His brother Lakshman as Sahodar, but that only goes to show His intense attachment and love for him. It was only proper and befitting to weep for the brother who was prepared to abandon everything and even to die and undergo all sorts of sufferings but by showing the limit of grief on this occasion the compassionate Lord showed to us mortals, how the brotherly affection should be like!

These pathos of the Lord are to be appreciated though compassionate heart, leaving behind all our intellects and wisdom behind. The Lord displays such human emotions to let us wretched mortals, who have dried up our heart's softness by indulging in worldly mundane activities, to get drenched in Divine Ras or nectar of Bhagvad Leelaa Anuraag (love for Lord's pastimes and His story)
[by Deepak Tiwari, Valmiki and Kamban Ramayan Group, May 3, 2009 ]