From memory these are generally unserviceable.
When you lower the leg, the shaft will rotate but will also move over a detent internally. Try and drop the leg half way so the internal spring is compressed, then look for the largest gap. Shove a spray straw in there and blast in white-lithium grease (not WD40) and work the leg back and forth.
These are not precision instruments, some force and persuasion may be required.
Don't cut it off, unlike mine, yours looks to be acting as a chainstay bridge, providing reinforcement. Removing it completely would be bad.