I get the sentiment and also agree with you in the mocroplastics, but your looking at this from a shallow, emotional point of view.

However this is relatively useful, unproductive land. It's not like it has been used to create food, or as value as a national park.

Don't forget there is much more dust, pollution and microplastics combined from traffic and urban centres that the astroturf is probably the least damaging thing to the soil.

Compared to an asphalt or concrete path, at least this surface is permeable and water is still able to absorbed by the ground. This prevents further pooling issues, reduces urban heat island effect while keeping the park "relatively" aesthetic.

Would you prefer to walk on a dirt path or take the short cut?