As @NIS and @Bohdan already pointed out, exactly the above statement is not true.
True statements are:
- SailfishOS uses device drivers made for Android.
- In contrast to that “Android App Support (AAS)” (original name: AlienDalvik) is a full AOSP-derived Android-distribution (like e.g. LineageOS, formerly called CyanogenMod) with some additional components (shared clipboard etc.), which runs in an LXC container (exactly like Waydroid / ex-Anbox).
But AAS is not an integral part of SailfishOS, it is a proprietary, optional add-on for which one needs to buy a license.