If one is familiar with organized sports, there is in general a strong difference between outdoor and indoor stadiums, and between the sorts of surfaces that teams play on as well as the effect of those surfaces on sports. (In tennis, the situation is even more complicated, with at least four different surfaces, three major ones in hardcourt, grass courts, and clay, and a minor surface in carpet.) In general, it can be said that grass is preferable as a forgiving playing surface but is also more difficult to cultivate, and given the desire of many people to control playing surface, astroturf is often used because it can be used indoor, and thus allows for greater convenience if not greater performance.
It is little surprise that astroturf has relevance far outside of athletics, and that the same concerns that one has about astroturf and grass with regards to sports is simultaneously a concern when one deals with these matters in metaphorical tendency. In questions of politics and anywhere there is a concern about popularity it is of considerable importance to know the difference between that which comes from the bottom up and that which is fostered from the top-down. In general, that which comes from the bottom-up has more legitimacy, and a deeper level of commitment, but that which comes from the top-down is easier to control and thus those who try to control things from the top-down and manipulate the appearance of mass appeal have a strong incentive to disguise such efforts to make them appear to be the genuine stirrings of ordinary people rather than the manipulation of people through bogus ideologies and efforts at command and control.
Astroturf, it must be remembered, is imitation grass. I do not think there is anything inherently wrong about imitating grass, and in seeking to expand the range of athletic competition beyond outdoor fields where the climate is friendly enough that grass can grow naturally or be easily grown by grounds crew. What is wrong is pretending that astroturf is grass, and in neglecting to counter the known disadvantages of astroturf, or in pretending that there is no difference between one thing and another. It is the dishonesty of the effort of metaphorical efforts at faking ground roots appeal that is troublesome and problematic, not the reality that political movements and powerful interests want the benefits of being seen as being at the vanguard of a popular movement without the awkwardness of having to know and motivate and inspire people in a legitimate and consensual manner.
What is to be done about this? Whether we are talking about the literal or the metaphorical nature of astroturf in our world, my own personal position is that we should cultivate grass where it can grow and where it is already found. This requires a great deal of effort at first, but such effort can be well rewarded when we grow what is best suited to our soil and climate conditions such as we find them, allowing us to ultimately expend less effort than it would take to force something that is unsuitable. Where grass cannot be grown, we should accept the necessity of using some sort of artificial surface, but should not hesitate to mitigate the negative consequences of that whenever possible, with an honest admission of the artificiality of what is going on, and without any attempt to disguise that reality from ourselves or from others. For it is self-deception that prevents us from recognizing reality and responding appropriately to it, and we are often far better at deceiving ourselves than we really are at fooling others, which is often an elusive goal that only seems successful because others recognize the folly of trying to point out what is obviously unwelcome truth and simply leave us to our own state.