Just to get the numbers clear: of the 206 male Gnomes, 46 have STR of 8 or less, 25 have STR 9, 27 have STR 10, 27 have STR 11, 25 have STR 12, and 56 have STR 13+. In that middle half (104 of 206) the only difference is in (i) the chance to BB/LG, and (ii) an encumbrance limit of 160 lb rather than 150 lb for the upper 25. So the average encumbrance limit for this group is 152.5 lb.
Of the 212 male Half-Orcs, 31 have STR of 8 or less, 21 have STR 9, 25 have STR 10, 27 have STR 11, 27 have STR 12, 25 have STR 12, and 56 have STR 14+. In the middle portion (104 of 212) with STR of 10 to 13, the only difference is in (i) the chance to BB/LG, and (ii) the upper half of that middle portion have an encumbrance limit of 160 lb rather than 150 lb. That's an average of 155 for this group.
For the middle half of both groups, there is no difference in their chance to hit or damage in melee. They have no difference in their chance to open stuck doors. There is a variation of 1% to 4% in an ability that is very rarely used - BB/LG. And there is, for the Half-Orc, an average encumbrance limit of 155 rather than 152.5 lb.
This is why I say the Half-Orcs are not, in any interesting way, stronger. If you need a bar bent, calling on a Half-Orc compared to a Gnome has a reasonable prospect of doubling your chance from almost no chance of success to just about almost no chance of success. And that's it.