To quote the grizzled old explorer Commander Lorn, from the short story "The Outer Limits" in the original Frontier: Elite II short story compilation "Stories of Life on the Frontier", when the shipyard mechanic tried to sell him some new lasers:
There is only one reason why an exploration ship would have weaponry of any kind: if you don't have an SRV with you, and you need to harvest some raw minerals for repairs or jumponium, a mining laser will liberate those ores for you from a convenient asteroid or ring-rock. You don't need the rest of the mining kit (eg a refinery) for the laser to extract raw materials.
Actual weapons, to blow up enemy ships with, are entirely redundant. Ideally, an exploration ship is stripped down, lightweight, all non-essential items removed to extract maximum range; they're basically life support cubes with giant engines attached to them. A ship like that is fragile as anything. An explorer about to dock at a space station after an exploration trip is also jam-packed with exploration data, worth a fortune but it's all lost if you get yourself blown up.
If you meet hostile aliens, you're dead, with or without weapons. If you meet friendly aliens, you don't want to go accidentally shooting them in your excitement. If you meet lost colonies of humans or the ancient remnant of rogue AI, same deal. If you meet other explorers, they're most likely in unarmed ships as well, so no threat. If you meet a psycho player-killer, you're dead no matter how many weapons you fly with.
An explorer has no business starting a fight, or trying to finish one. Be like Lorn. Run Away.