They are not ruling out the tsunami possibility, just saying it’s very unlikely. I’d agree. However, localized tsunamis caused by landslides have happened in Alaska. Luckily they were contained by the bays and coastal islands where they happened. The slippage of the Northwest American subduction zone has created tsunamis that did a lot of damage to Japan.
Las Palmas would be most likely if the volcano explosively erupted sideways (like St. Helens). Not a big chance but the likelihood isn’t 0.