Blood, which is not spilt as water is not Machshir - דם שאינו נשפך כמים אינו מכשיר
Summary:
The exclusion from being מכשיר לקבל טומאה is only regarding דם קדשים which is required to be received in a vessel, but not to דם חיה which is spilt לארץ but merely requires כיסוי. The law of כיסוי by דם חיה is despite the fact that it is נשפך כמים, since the תורה explicitly requires it.
Therefore, it does not bear but only the sin of Tum’oh which was exempted from its rule - הא אינו נושא אלא עון טומאה שהותרה מכללה
Summary:
ריצוי הציץ is applicable only to something which is הותר מכללו where the היתר is not the preferred mode of service. Thinking about חוץ למקומו is not יוצא and is considered 'לפני ה.