They say status quo antebellum since there were no territorial losses, but the British raided and burned Washington, right? Further at a glance it seems the British won many more victories, i remmeber hearing that the only undisputed American victory was at New Orleans and technically it was only after the war ended, but the parties hadnt heard the news.
The British did indeed have more impressive tactical victories (they won battles), but since the War of 1812 ended with neither side admitting defeat or giving concessions, that entire affair is considered "status quo antebellum" (the state existing before the war)
In fact, you also have wars where both sides can legitimately claim victory. For example, let's say Country A is aiming to capture or kill 20,000 enemies (limited pre-emptive strike due to supply shortage?) within 2 months and Country B is preparing to defend their homeland against invasion. Country A's troops do not push very far into Country B, but they exceed their kill count target by 30,000 when the deadline comes around. Country A pulls out, never having conquered a single Country B city
Country B could claim that they won the War of Resistance, the Homeland War, the Border War, or whatever name they give it. Country A could also claim that they won the War of Retaliation, the Punitive War, the War of Justice, or whatever name they give. Who won? They both achieved their goals. In fact, you could argue that they both wildly exceeded expectations. Country A more than doubled their target, and Country B did not lose a single city
And we have had wars like this. The Aztecs, for example, did not always wage wars of conquest, and Ancient China saw some multi-sided affairs in which one kingdom willingly sacrificed massive portions of land and agricultural production to one kingdom's sneak attack so that it could finally destroy the capital of a long-hated enemy for revenge
Because they didn't win. Regarding American victories, there were many most notably probably being Lake Erie, Thames, Chippewa, Baltimore and Champlain but given the nature of the war with many small battles being fought on the frontier with forts and towns frequently changing hands there were many more American victories that aren't particularly well known but are nonetheless decisive and important (like Fort Meigs). While Washington was raided, it didn't seem to have a large impact on the negotiations or American morale I suspect this is largely because news of American victories elsewhere and because of experiences during the American revolution.
Britain initially did have demands to impose on America, namely the retention of Northern Maine and a few key border forts, transit of the Mississippi, and a Indian buffer state. Defeats in the 1814 campaign, popular opposition to the war in Britain, and the opinion the Duke of Wellington (who didn't think Britain had accomplished anything to demand concessions from the US and also expressed doubts about his ability to win in America) all contributed to Britain basically agreeing to a return of the status-quo. Unfortunately for Britain the battle of New Orleans was fought before the treaty was ratified, so the popular view at the time in America and Europe was of an American victory.