First of all, Jeff Schewe's post means, that he *does think* that these steps should be done in the raw processing.
The underlying reason is the non-linear nature of mapping the originally linear raw data to the target color space (the color space definitions, unnecessarily, contain the mapping scheme as well).
Let's see the mapping of the 14bit linear data in sRGB; left the linear pixel values from 0 to 16383,, right the corresponding sRGB values, from 0 to 255.
1. The very dark end (apart from a small special segment at the beginning):
0060-0079: 012, 012, 012, 012, 012, 012, 013, 013, 013, 013, 013, 013, 014, 014, 014, 014, 014, 014, 015, 015,
0080-0099: 015, 015, 015, 015, 015, 016, 016, 016, 016, 016, 016, 016, 017, 017, 017, 017, 017, 017, 017, 018,
i.e. every six, later every seven, etc. linear values are mapped to the same sRGB value. After that, it is not possible to make distinction between the originally different values.
2. In the mid range:
3440-3459: 126, 126, 126, 126, 126, 126, 126, 126, 126, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
3460-3479: 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
3480-3499: 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
3500-3519: 127, 127, 127, 127, 127, 127, 127, 127, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
3520-3539: 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
3540-3559: 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
3560-3579: 128, 128, 128, 128, 128, 128, 128, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129,
3580-3599: 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129,
3600-3619: 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129, 129,
3620-3639: 129, 129, 129, 129, 129, 129, 129, 130, 130, 130, 130, 130, 130, 130, 130, 130, 130, 130, 130, 130,
now every 59, 60 linear value gets mapped on the very same sRGB value.
3. At one stop down from the bright end:
8160-8179: 187, 187, 187, 187, 187, 187, 187, 187, 187, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188,
8180-8199: 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188,
8200-8219: 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188,
8220-8239: 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188,
8240-8259: 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188, 188,
8260-8279: 188, 188, 188, 188, 188, 188, 189, 189, 189, 189, 189, 189, 189, 189, 189, 189, 189, 189, 189, 189,
97 different values (from 8169 to 8265) get mapped on the single sRGB value of 188.
4. At the very bright end:
16080-16099: 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 253, 254, 254, 254, 254,
16100-16119: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16120-16139: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16140-16159: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16160-16179: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16180-16199: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16200-16219: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16220-16239: 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254, 254,
16240-16259: 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
144 originally different values will appears as sRGB 254.
This enourmous compression is all right with 8bit monitors and printers anyway. However, if you decide to change the image a lot,, for example by decreasing the contrast (reducing the highlights) or by reducing the lightness, then many originally different pixels, which got mapped to the same value will appear with the same value but darker - although if you had reduced the lightness before mapping, some of those pixels could be distinguished from the others.
This is an irreversible process (a "lossy compression"), thus once you did the conversion, you better don't do aggressive changes any more.