This is the brand guide. But those colors are easier to keep consistent when printed on various paper stocks than getting cloth right.
Back in the day (I matriculated in the fall of '79) there was zero brand consistency. When schools began the push for registering their own marks was mostly when that started.
Note the RGB value of 500000 is pure, unsaturated RED (50 on a hexadecimal scale of 00 to FF is roughly 31.4% saturated red hence that dark hue.). There is no purple on screen.
Print processing uses CMYK four color and to achieve the same color and saturation it combines cyan (c), magenta (m), yellow (y), and black (k).
RGB works with light and is additive and FFFFFF is full intensity white because each color of each pixel (red, blue, green) is at full intensity. Blacks are much harder on a monitor because either the pixels leak backlight while printing a black ink can be fully saturated because it's a subtractive color palette. More color make it darker.
Also note the branding guidelines and licenses to use the marks are administered by the Office of Business Development. It's perfectly fine to contact them about licensed gear that you believe fails to follow the branding guide. Just keep in mind colors on cloth are much more difficult.
https://brandguide.tamu.edu/visual-style/brand-colors.html