You did not read the above carefully did you? The only command in that entire Hadith is when they say Qumoo.
Istigathaa has never been in the state of a command.
**
Edit:** I think I follow your train of thought now. Where did you get your translation from by the way? All the Arabic websites have understood as I have presented it but if you have a reliable source which is using it in the way you present it do give me the reference.