Yes, it's sad. As a SLP assistant, you have been providing therapy and helping patients for years. You do almost the same thing as a licensed SLP except for "diagnosing", planning treatment plans, supervision, and signing on reports, etc iirc. It's indeed sad that the gatekeepers at the grad schools disqualify candidates based on their grades on courses taken years ago. It's analogous to disqualifying qualified candidates for college based on the grades they got long ago in grade school. Not everyone takes the same path in life. People can be late-boomers or were disadvantaged earlier in life.