I am not surprised by this, and such discounts are given to the citizens of the host nation every time they stage the world cup. And in case of Qatar, it should not matter much. Do you know why? Because Qatar do have only around 300,000 citizens (and all of them may not be interested in watching football). Millions of tickets are available for sale and the number of tickets is greater than the number of Qatari citizens (only around 10% of the population of Qatar is made up of nationals). Some of the stadiums in Qatar can accommodate the entire Qatari national population in one go.
Apart from that Qatar is rich countyr. There GDP per capita (current US$) in 2020 is 50k$ according to
world Bank data , so giving discount to there citizens is not a big deal for Qatar.
It's not not people of Qatar who will be there to watch the World Cup but spectators from entire globe will come to see that event and that's where Qatar will be targeting to earn profit.
Qatar is the richest country and only has a population of less than 3 million, even the state of Qatar pays their workers wages of 350k per hour, even though the government does not give discounts to its citizens, I am very sure their citizens are not angry, the Qatari government only wants to profit from immigrants , they managed to host the world cup, their goal is to show the world that their country is a safe country and none of their citizens live suffering,
they used it to attract local viewer on this huge event, its not funny if world cup even meanwhile Qatar's citizen not interested with it. they have alot money and everything could do by this, even some owner of footbclub come from this country. this international event that will alot tourist from abroad and helpfull in future they come here again while mesmerized by the beauty of the city