Why? It's true that liberals talk about freedom of choice. This choice, though, is to be exercised by a stripped-down version of the individual: one who is no longer "encumbered" (to use a liberal term) by what is inherited or inborn.
Nor can our liberal individual ask for a particular social setting in which to fulfil his life aims. He must instead pursue those aims which he can achieve by himself independently of the social setting.
What are the areas of life that give us a range of choice and which we can pursue as independent, self-defining individuals? The obvious ones are careers, travel, entertainment, restaurants and shopping. These fields are very much open to individual choice, so it's not surprising that a liberal society is very good at developing them.
In his article, Jim Kalb discusses another reason for the liberal restriction on life aims. He looks at liberalism as a particular system of managing society, a "comprehensive system of top-down-social management". The principle of this system is "the efficient and equal pursuit of individual desire".
It is a universal system which does not like to recognise qualities or distinctions outside itself, such as those related to family, culture, religion and inherited community. In fact, the more that these non-liberal distinctions are disrupted and suppressed, the easier it becomes for a more formal, centralised, technocratic system run by a liberal bureaucratic elite to manage society.
I'll finish with some relevant extracts from Jim Kalb's article (but I've had to compress the argument - it's worth reading the whole article):
Left-liberals believe that society is made up of individuals and legal structures. The only rational and legitimate purpose of the structures is to give the individuals whatever they happen to want, as much and as equally as possible. It follows that the purpose of government, and indeed of morality, is regulating individuals and structures so that career, consumption, and the free choice of hobbies, lifestyles, and indulgences are secured for everyone.
... The goal is to give people what they want, and it can only be achieved if what people want fits into the liberal scheme: that is, if it respects the needs of the system and the equal validity of the desires of other individuals.
That means that what people want has to be controlled. Left-liberalism requires us all to become virtuous, where virtue consists in pursuing only legitimate desires — in other words, supporting the system and otherwise minding our own business by concerning ourselves only with tolerant and private goals. Hence PC, and hence the constant re-education initiatives to which we are now subjected.
... The point is abolition of all non-liberal institutions, loyalties, and standards. Those things lead to inequalities not justified on liberal grounds. They propose non-liberal goods — God, country, family, virtue, whatever — that interfere with the smooth operation of a system based on the efficient and equal pursuit of individual desire simply as such.
It is therefore basic to the liberal view that people must be made to view non-liberal goods and institutions as wrong and shameful. In particular, they must be taught to reject with disgust distinctions not related to the functioning of liberal institutions...
All history, all nature, all culture, and all religion threaten the basis and functioning of a liberal social order. They tell us that human beings cannot be reduced to orderly productive consumers who do what they’re told and only want a life of measured private self-indulgence.
Since human nature is a problem for liberalism, as all indications tell us it is, it has to be denied and stamped out. That is why liberals see hatred, bigotry, and intolerance everywhere. Crypto-Nazis are under every bed. The people can’t be trusted, so they’ve got to be disarmed, supervised, regulated, re-educated, and kept away from anything serious.