Short answer
Wikipedia: Pressure (symbol $p$ or $P$) is the force applied perpendicular to the surface of an object per unit area
So direction of the force caused by pressure is determined by surface orientation.
If pressures at A and B were different, horizontal pressure force would be pushing fluid from higher pressure to lower one to equalise the pressure.
Longer answer
Pressure is not a force and it has no direction.
Yes, it can be said it is a thrust downwards on a given area. Or upwards. Or leftwards. Or right/front/rear/any direction-wards.
Pressure can be defined by 2 ways:
$$\mathrm{1\ Pa = 1\ Nm^{-2} = 1\ Jm^{-3}}$$
Acceleration $\vec a$ of a fluid element is
$$\vec a=\vec g - \frac {\vec {\nabla p} }{\rho}$$
where $\vec g$ is gravity acceleration
and the second term is pressure gradient divided by fluid density.
In the static fluid case, horizontal forces caused by pressure are mutually cancelled and vertical forces caused by pressure gradient are cancelled by the layer force of weight.
If pressures at A and B ( on the same horizontal level) were different, then fluid would flow horizontally until they were the same, as the net force acting on thought fluid segment would be nonzero and horizontal.
Hurricanes are attempts to equalise horizontal pressure gradients, turned to circular motion by the Coriolis force. If the Earth had not rotate, they would not have existed, nor the pressure highs and lows, and gradients would have been cancelled quickly.
The same vertically, if $ \mathrm{d} p <> - \rho \cdot g \cdot \mathrm{d}h$
If you push fluid away in any direction you do work against the pressure
by raising its position potential energy by displacement or
raising its compression potential energy, or
raising its kinetic energy.
In real cases, it is usually combination of above.