His criticism is directed against lawyers, not against philosophers and practical diplomatists.
[1] The language of this treatise is noteworthy.

After discoursing on the differences between republics and principalities, and showing that Florence is more suited to the former, and Milan to the latter, form of government, he says: 'Ma perche _fare_ principato dove starebbe bene repubblica,' etc.

...

'si perche Firenze _e subietto attissimo di pigliare questa forma_,' etc.

The phrases in italics show how thoroughly Machiavelli regarded the commonwealth as plastic.