Where is the Fighter picking up the Wizard's free rituals from?
One of the feats that lets you multiclass into Wizard gives you their full Ritual Casting feature (including learning new rituals as you level up). A Hybrid Wizard does not get access to this feature (even via Hybrid Talent), and since they are already a wizard, cannot take the multiclassing feat.
They can take Ritual Caster normally, but that does not grant the free learning of rituals as they level. Hence, the fighter who multiclasses into wizard with one feat is better at rituals than the hybrid wizard/whatever.