Even though all the strong members of the Shenxiao Sect were aware that the successor to the Sect Leader wasn't just chosen from among the True Immortals and the many other Supreme Overlords who possessed the combat power of a True Immortal but had yet to certify their Tao.
Expanding this range to include all Supreme Strong would naturally come with many stringent requirements and conditions, likely to disqualify many, yet still unable to dampen their enthusiasm.
After all, when faced with the arrival of an opportunity, whether one is qualified is very important.
If it was explicitly confined to True Immortals and Supreme Overlords with the strength of True Immortals, ordinary Supreme Strong would undoubtedly feel somewhat disappointed without needing to say anything.
However, if they were to be included in this range, they would know they had no chance and did not meet the qualifications and would be excluded, yet they would feel much less resentment.