The suggested items were titanic hydra (50 ad) and Steraks Gage (25% base ad, and another 25% when shield pops).
Titanic hydra may give 50 ad, but its passive scales off of the maximum health of the user and it provides split push potential. It also boosts hp5 and doesn't have lifesteal (because you're right, tanks don't build a lot of ad to make lifesteal worth it). So, Titanic is a great tank item. If you are confused about the 50 ad, don't be; attack damage is good on all champions, because there is no cost on auto attacking. Its also essential to get some ad or ap on a champion that is going to split push, because without one of these, its really hard to take towers.
Steraks Gage amplifies base ad, or the ad that is gained through level ups but not through runes or items. This makes Steraks a phenomenal pickup on a tank because they have higher base auto attack damage and usually higher ad growth per level, making that 25% boost more effective on them than on other champion types. Secondly, the shield Steraks provides is based off the maximum health of the user making it, again better on tanks that invest more in health. See a theme yet? Finally, shields scales off resistances that the user has, so a shield for 30% of the users max health plus the resistances from other items/ abilities makes it an even better item for tanks looking to absorb damage.
Basically, the only items they suggested that shen build with attack damage are both heavily oriented towards tank champions.