But that's moving the goal-post from '4E didn't have the Healer Cleric' to 'The very first book didn't have the Healer Cleric'.
To someone who only bought the first book, that very first book is the entirety of 4E. In the same way, it was the entirety of 4E for everyone, before additional books were released. Anyone who bases an opinion on that sort of information is entirely correct, when accounting for those constraints. The map is not the territory.
You couldn't play a focused healer-type cleric in core 4E - you were limited to two words per encounter, and possibly some other abilities at higher levels, but most importantly it didn't take your action to heal. If you wanted to play the healer type, you were expected to attack things every round, which really kills the feel of the character.
However, complaining that the 1st rulebook did not provide a specific option, though valid, IMO misses the point of a new rule edition. I could not play a barbarian or a sorcerer either. I was equally unhappy at the edition change to 4e based on the options available at first printing, but they met the baseline for the most part in getting the main class concepts in the game. This was especially true given the desire to separate healing from character options in combat. This has been the complaint for most players IME as relates to clerics for 30+ years.