To the extent that this is even true it appears to be caused by three things: stock option compensation accounting, R&D deductions and bonus depreciation.

Stock option compensation rules have been a boon because Meta stock has risen 6x in three years. It's unlikely to do that again. My understanding is that this is symmetrical so if the stock trends down we will see an inflated effective tax rate for Meta.

Recent R&D rule changes allowing software engineering salaries for R&D to be written off seem reasonable and were quite popular on Hacker News. Previously these expenses were amortized over five years so this just pulls it forward. Subsequents years will see depressed expenses.

Bonus depreciation is once again just pulling forward legitimate expenses earlier than before. At worst they are just delaying giving the government its taxes and the corporations gain a few points of interest in between.

All of the tax rules used here are open to debate but none seem obviously wrong or nefarious. This is why people like Reich choose to keep things vague. Corporations brazenly stealing from your pocket is much more interesting than the mundane reality.