Because an objective science minded person would realize based on the information provided that statements like "When high stakes are at risk like the Earth's ecosystem its important to be sure of your facts," are silly when there are risks associated with either doing or not doing MSR.

There is no science saying Martian life will be hazardous. The scientific consensus is that it might be hazardous but that it most likely is not. There is also absolutely no scientific basis for claiming reliable containment can't be acheived. We don't have to rely on just theory either. Tests can be conducted.

Your question "What is the benefit of a Mars Sample Return other then satisfying a handful of astrobiologists and Mars advocates?" is a blaring statement of your low level of understanding of the science of biology. An example of truly alien biology would be an immense boon to advancing biological science. Many advances in biology lead to better medicine of immense interest to every single human on the planet. Is it worth almost no risk to make major advances in biology? You bet your you know what it is.

If there is no life on Mars the samples would be of much less interest, but the risk would be far less even than the miniscule risks posed by Martian life. Fossils of past life would still be a fantastic scientific discovery. Even plain geological samples would be of great value in understanding Mars history given the vastly greater analytical capabilities on Earth.

RE: "And why the Hurry? Why not just wait a few years more until NASA sends astronuts there? Afterall they are paid to take these kind of risks. Or do you now believe that sending humans to Mars without knowing first if life exists and is harmless is too risky?"

Do I now believe? So when have we corresponded before? Careful their Mr anonymous handle your cover might slip off. I'm OK with sending humans to Mars without MSR, but a lot of people aren't. Fortunately I see a lot of value in MSR and little risk so I see no reason to argue much with them. Whether we do MSR or not I also think we should assess life on Mars again using more modern and reliable technology than that used on Viking once NASA's program identifies the most likely spots on Mars. I'm sure we can do better now than experiments designed by the likes of Gil Levin even if his suggestion of a repitition with different optical forms would be a vast improvement.

Regards,
Mark