I'm almost certain they're talking about mortality rates. Covid is definitley closer to Spanish Flu's mortality rate than the previous 3 flu pandemics. Swine Flu's mortality was as little as 0.02%. The 2 forgotten pandemics: Asian Flu and Hong Kong Flu were 0.67% and 0.4% respectively. COVID is around 4%, that is much higher than the others and much closer to Spanish Flu's. If Swine Flu had infected EVERY SINGLE PERSON in the US, there would be less deaths than COVID has killed in the US while infecting only 1.7% of the population. You have to think about that too, COVID has not infected a massive amount of people like the Flu pandemics. 21 Million people have been infected compared to Spanish Flu's 500 Million and Swine Flu's 760 Million - 1.4 Billion. Swine Flu may have infected 67x times as many people as COVID and killed a THIRD as much making it possibly 200x less deadly than COVID. Let's say COVID were to infect as many as Spanish Flu did, 500 Million. With it's 4% mortality, it'd be 20 Million dead. COVID is a deadly virus, much more than Asian and Hong Kong Flu, and WELL WELL ABOVE Swine Flu. It is more comparable to Spanish Flu. They are polar opposites though on who it usually kills. Spanish Flu killed healthy people the most, COVID kills people over 65 or with underlying conditions most.
Also, don't say the word "only" when referring to deaths. 760,000 is more than just a number. Each one of those is somebody has who lost their life. Roughly 1 in 10,000 people worldwide. You can say Spanish Flu did kill a lot more because it definitely did, but don't use the word "only". I think that's disrespectful. The amount of people killed by COVID worldwide is higher per-capita than people in NYC who died from 9/11. That was about 1 in 25,000 people in NYC. We're not gonna say that only 3,000 people died of 9/11. That was more tragic, but any loss of life is tragic. If it's 2, don't say just 2. 760,000 may not look big when referring to the world, but it is a massive number. I doubt any of us have seen 760,000 people at the same time in one place. If we did, it'd be a sea of people... all of which have died.