In addition to not yet having taken the land, the government doesn't want to take the land, and the government knows and accepts that it cannot take the land, make changes to the land, or demand from someone else to make changes to the land using the process of designation of critical habitat (which is what this issue is about).
As the court document that DavePhD found states:
Following designation, the Fish and Wildlife Service cannot force private landowners to introduce endangered species onto their land or to make modifications to their land
The service is also aware that they cannot take the land or make changes to the land:
Service candidly recognized in the Final Rule that it could not undertake any efforts to change the current features of the land or to move frogs onto the land without the permission and cooperation of the owners of the land.
"want to" in this case means "hope that other people will, but will not enforce or demand changes". The hope is important for the designation as critical habitat, but it is just that: hope.
Specifically, the current economic activity on the land will not be impacted by the designation:
The proposed designation of critical habitat for the dusky gopher frog would not result in physical occupation or invasion of private property. On non- Federal lands, activities that lack Federal involvement, such as timber management and oil and gas extraction, would not be affected by the critical habitat designation.
However, future changes in the economic activity that involve the federal government may be regulated:
However, a second scenario concerns activities of an economic nature that are likely to occur on non-Federal lands in the area encompassed by this designation, and where Federal involvement may occur, and includes construction of utilities, residential or commercial development, and road construction and maintenance. This second scenario is where a regulation may potentially deny all economically beneficial or productive use of land, commonly referred to as a categorical taking. However, the mere promulgation of a regulation designating critical habitat does not on its face deny property owners all economically viable use of their land. The Act does not automatically restrict all uses of lands that have been designated as critical habitat, but only imposes restrictions under section 7(a)(2) on Federal agency actions that may result in destruction or adverse modification of critical habitat.
The designation of critical habitat does not impose a legally binding duty on private parties. Activities that do not involve a Federal agency, Federal action, Federal funding, or Federal permitting, will be unaffected by the designation of critical habitat. Private land use activities, such as farming and silviculture, would be unaffected. Federal activities, or actions permitted, licensed, or funded by Federal agencies, will require consultation with the Service if they are likely to adversely modify critical habitat.
The consultation may result in the demand of "reasonable and prudent alternatives", which must be economically feasible. Again, this is only the case if the federal government is involved in the development, otherwise no consultation is required.