The places they are aiming this at are:
Lisbon, which, between regular tourism and encouraging "digital nomads," has lost many apartments to AL status, Porto, where the same is true to a lesser effect, and the Algarve's beach towns.
In all these areas, there is a severe housing shortage which impacts business because employees cannot find affordable places to live. (Same thing happening in any tourist-dependent major city in Europe and North America.) Thus the new law, which is a response to a housing crisis locally.
Of course those subject to the new law and tax are indignant about it. It should not affect peregrinos at all. A non-issue in the rural areas north of Lisbon where AL are exempt from this law.