Why keep people and kick out others...

did they do that here, sorry i don`t why but would like to know why myself

Simple. Take a look at the rule book. If you do not like it, get out. If you can not live with it, "it" will kick you out. Remember, not all people are cut-out for military life. I really do not care if you want to stay or not, follow the rules, it is a volunteer uniformed service.

Thats the sort of intolerance that makes service members like myself choose not to re-enlist.

The answer is usually not as simple as the 'Rule book' as senior chief would suggest, it's usually a combination of a loose interpretation of the rules (and such an interpretation would never hold up in an actual court of law) and the politics of your command. Most notably how well liked you are, and what the rank of the people who favor you are.

Don't let anyone convince you however that upon administrative separation, or some other form of OTH that you will end up flipping burgers for the rest of your life. Simply move on, While I agree with Senior Chief that military life isn't for everyone, and it certainly is a volunteer uniformed service, just because you do not succeed in it does not mean you will not, or can not be successful in other avenues in life as many may suggest (if you have a DD-214 with an OTH separation). I know several people from my command who were discharged for relatively frivolous reasons and had more to do with their division not liking them than anything they did wrong and they are making in excess of 6 figures and doing quite well within 4-5 years of working in the private sector.