While I believe that life arose spontaneously some 3.5 BYA, .....
Since that is still an open question, scientifically, it should be
presented as such in textbooks. To imply more is disingenuous.
But this is part of the problem with textbooks. When all they do is
present factoids, it is hard for the students to separate out the
well-established factoids from the speculative ones. The easiest
things to prove by appeal to authority are the false things.
Science education will, IMO, only be a well-taught subject when we
put the emphasis on the process rather than on the results. Both are
important, but the results are tentative, the process is not.