Weather sealing is like the lottery – some people use Rebels in the rain (I’ve seen that) with no problems, others report water damage to 1-series bodies in similar conditions.
At issue is not your personal experience/luck, but rather the type and extent of sealing Canon uses on the camera. As one example, recent 1-series bodies and the R3 have O-rings under buttons, bodies with second-tier sealing (7DII, 5DIV, R5) have foam.
The point is that Canon stated the 7-series DSLRs had weather sealing equivalent to that on older 1-series DSLRs, e.g. the 1DIIN. The R7 has third-tier sealing similar to later xxD DSLRs, which is not as robust as the 7-series DSLRs.
It’s another way in which the R7 is not a mirrorless 7DIII.