The cuddly Xavier is from the 90s. It was brief and only came about from the X-Mem TAS show which did a terrible job representing the real Xavier.
His stint as nice was brief as even in the 90s we got Onslaught. And X-Men Hidden Years which is a laugh. And then the 00s we got more skeletons.
Even during the New Mutants era he was an *******.