IRS laws say you can deduct $3000 ordinary income (i.e. income earned by working, so doesn't include capital gains) per year and deduct without limit against capital gains. Should your capital losses exceed your capital gains that year, you can carryforward the rest of the capital losses without limit onto the next year 2023, 2024, etc.
The whole point of the article is that "tax loss harvesting" beneficial to Steve Ballmer and the other billionaires mentioned in the article, because they have $Bs in capital gains to begin with (Steve Ballmer had highly appreciated MSFT stock as mentioned in the article). An average Joe like you and me even if we have that much capital losses would find it difficult to find the capital gains to deduct against, so we're typically limited to only $3000 per year deducting against ordinary income (compare against no limit for capital gains), which is much less useful tax shield compared to someone like Steve Ballmer who gets most of his income from capital gains, and who therefore can use his massive cap losses to shield against taxation much more effectively. This is the part that makes "Although this is also available to masses" somewhat moot. Even though it's "technically" possible, the masses don't have the massive capital gains to actually deduct against, so they don't benefit from this to nearly the same magnitude as someone who draws most of their income from capital appreciation.
Therefore, one could argue that this section of the tax code is "unfair" in year 2023. The article makes the case that wash sale rule was effective in the 1920s, but that in the 100 years that have passed, technology has made evading the wash sale rule trivial (especially for billionaires), so the rule as drafted in the 1900s is no longer effective at preventing what it intended.
Edit: I thought that limit is just for your ordinary income but there seems to be disagreement on this?