It appears that the new rules target the wealthy rich market and individuals with no connection to or do not want connection to their Thai wives or husbands. Individuals married to Thais are and can buy land already.
If this is the market, then the fear will rightly be that rich and wealthy can skirt all laws and buy more than what the law allow through loopholes in laws, lack of enforcement or otherwise.. then in a very short time u will see Thailand being bought by all foreigners.
So the fear is justified.