"We always convert your money at the live rate: the rate on Google." But this is a lie - I checked. At time of writing, you claim 100k GBP is equal to 131390 USD, while Google claims it's 131620 USD, a difference of nearly $300! Even saying "the live rate" is a lie. There is no one "live rate" (and therefore no "the" live rate). The price depends on your liquidity providers. IBKR shows "the live rate". Revolut shows…
It’s not a lie. It’s that it’s more complex than can be expressed in simple terms. Getting overly technical can be counterproductive.
I'd agree with you if it were unavoidable but I don't think that's the case here. There's no need to make a statement that there's a single rate.
For example: "we give you the best price we can find on the international market, without markup". It still states the goal without raising the falsehood of a single price.